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                                                                    Exhibit 10.1

                                                                  Execution Copy

                          REGISTRATION RIGHTS AGREEMENT

                                 by and between

                     DARWIN PROFESSIONAL UNDERWRITERS, INC.

                                       and

                        ALLEGHANY INSURANCE HOLDINGS LLC

                            Dated as of May 18, 2006

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                          REGISTRATION RIGHTS AGREEMENT

          This REGISTRATION RIGHTS AGREEMENT (the "Agreement") is made and
entered into as of May 18, 2006, by and between Alleghany Insurance Holdings
LLC, a Delaware limited liability company ("AIHL"), and Darwin Professional
Underwriters, Inc., a Delaware corporation and a majority owned subsidiary of
AIHL (the "Company"). Certain capitalized terms used herein are defined in
Section 1 of this Agreement.

          WHEREAS, as of the date hereof, AIHL owns approximately 90% of the
issued and outstanding voting securities of the Company and the management of
the Company, through a restricted share program, holds the balance of the issued
and outstanding voting securities of the Company; and

          WHEREAS, the Company has previously filed the IPO Registration
Statement (as herein defined) with the Securities and Exchange Commission but it
has not yet become effective; and

          WHEREAS, immediately following the consummation of the IPO (as herein
defined), AIHL will continue to own more than 50% of the outstanding voting
securities of the Company; and

          WHEREAS, the Company has agreed to provide the registration rights
specified in this Agreement, on the terms and subject to the conditions set
forth herein.

          NOW, THEREFORE, in consideration of the mutual covenants and
agreements hereinafter contained and for other good and valuable consideration,
the receipt and sufficiency of which are hereby acknowledged, the parties hereto
agree as follows:

1. Certain Definitions. As used in this Agreement, the following terms shall
have the meanings ascribed to them below:

          "Affiliate" means (i) with respect to any Person, any other Person
directly or indirectly controlling or controlled by or under direct or indirect
common control with such specified Person or (ii) with respect to any
individual, shall also mean the spouse or child of such individual; provided,
however, that neither the Company nor any Person controlled by the Company shall
be deemed to be an Affiliate of any Holder.

          "Business Day" means any day other than a Saturday, a Sunday, or a day
on which banking institutions located in the State of New York are authorized or
obligated by law or executive order to close.

          "Common Stock" means the shares of Common Stock of the Company and any
equity securities issued or issuable with respect to the Common Stock in
connection with a reclassification, recapitalization, merger, consolidation or
other reorganization.


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          "Common Stock Equivalents" means any securities convertible into, or
exercisable or exchangeable for, shares of Common Stock.

          "Exchange Act" means the Securities Exchange Act of 1934, as amended.

          "Holder" or "Holders" means AIHL and, subject to Section 4.5(a), any
party who shall hereafter acquire and hold Registrable Securities.

          "IPO" means the initial public offering of shares of Common Stock as
contemplated by the IPO Registration Statement.

          "IPO Registration Statement" means the Company's Registration
Statement on Form S-1, Registration No. 333-132355, of the Company, as
supplemented and amended from time to time.

          "Major Holder" means, with respect to any registration statement, the
Holder that, together with its Affiliates, includes the largest number of
Registrable Securities covered by that registration statement.

          "Person" means any individual, corporation, limited liability company,
limited or general partnership, joint venture, association, joint-stock company,
trust, unincorporated organization or government or any agency or political
subdivisions thereof.

          "Registrable Securities" means any (a) shares of Common Stock held by
AIHL and (b) shares of Common Stock issued or issuable, directly or indirectly,
with respect to the Common Stock referenced in clause (a) above by way of stock
dividend, stock split or combination of shares.

          "SEC" means the Securities and Exchange Commission.

          "Securities Act" means the Securities Act of 1933, as amended.

2. Registration Rights.

     2.1. Demand Registrations.

     (a) Subject to the terms and conditions of this Agreement, at any time and
from time to time after the date hereof, the Holders shall have the right to
require the Company to file a registration statement under the Securities Act
covering all or any part of their Registrable Securities on six (6) separate
occasions in the aggregate, by delivering a written request therefor to the
Company specifying the number of Registrable Securities to be included in such
registration and the intended method of distribution thereof (including, but not
limited to, an underwritten offering). All such requests pursuant to this
Section 2.1(a) are referred to herein as "Demand Registration Requests," and the
registrations so requested are referred to herein as "Demand Registrations"
(with respect to any Demand Registration, the Holder making such demand for
registration being referred to as the "Initiating Holder"). As promptly as
practicable, but no later than ten days after receipt of a Demand Registration
Request, the


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Company shall give written notice (the "Demand Exercise Notice") of such Demand
Registration Request to all other Holders of record of Registrable Securities.

     (b) The Company, subject to Sections 2.3 and 2.6, shall include in a Demand
Registration (x) the Registrable Securities of the Initiating Holder and (y) the
Registrable Securities of any other Holder which shall have made a written
request to the Company for inclusion in such registration (which request shall
specify the maximum number of Registrable Securities intended to be disposed of
by such Holder) within 10 days after the receipt of the Demand Exercise Notice.

     (c) The Company shall, as expeditiously as possible, use its reasonable
best efforts to (x) effect such registration under the Securities Act
(including, without limitation, by means of a shelf registration pursuant to
Rule 415 under the Securities Act if so requested and if the Company is then
eligible to use a shelf registration) of the Registrable Securities which the
Company has been so requested to register, for distribution in accordance with
such intended method of distribution, and (y) if requested by AIHL, if AIHL is
participating in such registration, or if requested by the Initiating Holder, if
AIHL is not participating in such registration, obtain acceleration of the
effective date of the registration statement relating to such registration.

     (d) The Demand Registration rights granted in Section 2.1(a) to the Holders
are subject to the following limitations: (i) with respect to any registration
in respect of a Demand Registration Request initiated by a transferee of AIHL,
such registration statement must include shares of Common Stock representing in
excess of 20% of the Registrable Securities then outstanding; (ii) the Company
shall not be required to cause a registration pursuant to Section 2.1(a) to be
declared effective within a period of 180 days after the effective date of any
registration statement of the Company effected in connection with a Demand
Registration Request; and (iii) if the Board of Directors of the Company, in its
good faith judgment, determines that any registration of Registrable Securities
should not be made or continued because it would either (A) require under
applicable law disclosure of material non-public information regarding
confidential business activities of the Company and such disclosure at that time
would be materially detrimental to the Company and its stockholders or (B)
materially interfere with any material financing, acquisition, corporate
reorganization or merger or other transaction involving the Company or any of
its subsidiaries (each, a "Valid Business Reason"), the Company may postpone
filing a registration statement relating to a Demand Registration Request, or
may cause such registration statement to be withdrawn and its effectiveness
terminated or may postpone amending or supplementing such registration statement
until such Valid Business Reason no longer exists, but in no event for more than
three months (such period of postponement or withdrawal, the "Postponement
Period"); and the Company shall give written notice of its determination to
postpone or withdraw a registration statement and of the fact that the Valid
Business Reason for such postponement or withdrawal no longer exists, in each
case, promptly after the occurrence thereof; provided, however, that the Company
shall not be permitted to postpone or withdraw a registration statement after
the expiration of any Postponement Period until six months after the expiration
of such Postponement Period without the prior written approval of AIHL.


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     (e) If the Company shall give any notice of postponement or withdrawal of
any registration statement, the Company shall not, during the period of
postponement or withdrawal, register any Common Stock, other than pursuant to a
registration statement on Form S-4 or S-8 (or an equivalent registration form
then in effect). Each Holder of Registrable Securities agrees that, upon receipt
of any notice from the Company that the Company has determined to withdraw any
registration statement pursuant to clause (iii) above, such Holder will
discontinue its disposition of Registrable Securities pursuant to such
registration statement and, if so directed by the Company, will deliver to the
Company (at the Company's expense) all copies, other than permanent file copies,
then in such Holder's possession of the prospectus covering such Registrable
Securities that was in effect at the time of receipt of such notice. If the
Company shall have withdrawn or prematurely terminated a registration statement
filed under Section 2.1(a) (whether pursuant to Section 2.1(d)(iii) or as a
result of any stop order, injunction or other order or requirement of the SEC or
any other governmental agency or court), the Company shall not be considered to
have effected an effective registration for the purposes of this Agreement
(including, without limitation, for purposes of Section 2.1(c) above) until the
Company shall have filed a new registration statement covering the Registrable
Securities covered by the withdrawn registration statement and such registration
statement shall have been declared effective and shall not have been withdrawn.
If the Company shall give any notice of withdrawal or postponement of a
registration statement, the Company shall, at such time as the Valid Business
Reason that caused such withdrawal or postponement no longer exists (but in no
event later than three months after the date of the postponement or withdrawal),
use its reasonable best efforts to effect the registration under the Securities
Act of the Registrable Securities covered by the withdrawn or postponed
registration statement in accordance with this Section 2.1 (unless the
Initiating Holder shall have withdrawn such request, in which case the Company
shall not be considered to have effected an effective registration for the
purposes of this Agreement, including, without limitation, for purposes of
Section 2.1(c) above).

     (f) The Company, subject to Sections 2.3 and 2.6, may elect to include in
any registration statement and offering made pursuant to Section 2.1(a), (i)
authorized but unissued shares of Common Stock or shares of Common Stock held by
the Company as treasury shares and (ii) any other shares of Common Stock which
are requested to be included in such registration pursuant to the exercise of
piggyback rights granted by the Company after the date hereof which are not
inconsistent with the rights granted in, or otherwise in conflict with the terms
of, this Agreement ("Additional Piggyback Rights") provided, however, that such
inclusion shall be permitted only to the extent that it is pursuant to and
subject to the terms of the underwriting agreement or arrangements, if any,
entered into by the Initiating Holder.

     (g) In connection with any Demand Registration that is an underwritten
offering, if AIHL is participating in such Demand Registration, then AIHL shall
have the right to designate the lead managing underwriter and each other
managing underwriter for such registration; provided that the lead managing
underwriter and each such other managing underwriter is reasonably satisfactory
to the Company, it being understood and agreed that either of Merrill Lynch &
Co. or Credit Suisse shall be deemed to be satisfactory to the Company. If AIHL
is not participating in the Demand Registration, then the Company shall have the
right to designate the lead managing underwriter for


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such registration, provided that such lead managing underwriter shall be
reasonably satisfactory to the Initiating Holder, and the Initiating Holder
shall have the right to designate one managing underwriter other than the lead
managing underwriter in any such registration, provided that such managing
underwriter selected by the Initiating Holder is reasonably satisfactory to the
Company, it being understood and agreed that either of Merrill Lynch & Co. or
Credit Suisse shall be deemed to be satisfactory both to the Company and to the
Initiating Holder.

     2.2. Piggyback Registrations.

     (a) If, at any time, the Company proposes or is required to register any of
its equity securities under the Securities Act (other than pursuant to (i) a
registration statement on Form S-4 or S-8 (or an equivalent registration form
then in effect) or (ii) a Demand Registration under Section 2.1) on a
registration statement on Form S-1 or Form S-3 (or an equivalent general
registration form then in effect), whether or not for its own account, the
Company shall give prompt written notice of its intention to do so to each of
the Holders of record of Registrable Securities. Upon the written request (the
"Piggyback Request") of any such Holder, made within 10 days following the
receipt of any such written notice (which request shall specify the maximum
number of Registrable Securities intended to be disposed of by such Holder and
the intended method of distribution thereof), the Company shall, subject to
Sections 2.2(b), 2.3 and 2.6 hereof, use its reasonable best efforts to cause
all Registrable Securities covered by Piggyback Requests to be registered under
the Securities Act (with the securities which the Company at the time proposes
to register) to permit the sale or other disposition by the Holders (in
accordance with the intended method of distribution thereof) of the Registrable
Securities to be so registered. There is no limitation on the number of such
piggyback registrations pursuant to the preceding sentence which the Company is
obligated to effect. No registration effected under this Section 2.2(a) shall
relieve the Company of its obligations to effect Demand Registrations.

     (b) If, at any time after giving written notice of its intention to
register any equity securities and prior to the effective date of the
registration statement filed in connection with such registration, the Company
shall determine for any reason not to register or to delay registration of such
equity securities, the Company may, at its election, give written notice of such
determination to all Holders of record of Registrable Securities who made timely
Piggyback Requests and (i) in the case of a determination not to register, shall
be relieved of its obligation to register any Registrable Securities in
connection with such abandoned registration, without prejudice, however, to the
rights of Holders under Section 2.1, and (ii) in the case of a determination to
delay such registration of its equity securities, shall be permitted to delay
the registration of such Registrable Securities for the same period as the delay
in registering such other equity securities.

     (c) Any Holder shall have the right to withdraw its Piggyback Request by
giving written notice to the Company of its request to withdraw; provided,
however, that (i) such request must be made in writing prior to the earlier of
the execution of the underwriting agreement or the execution of the custody
agreement with respect to such registration and (ii) such withdrawal shall be
irrevocable and, after making such


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withdrawal, a Holder shall no longer have any right to include Registrable
Securities in the registration as to which such withdrawal was made.

     2.3. Allocation of Securities Included in Registration Statement.

     (a) If any requested registration pursuant to Section 2.1 involves an
underwritten offering and the lead managing underwriter of such offering (the
"Manager") shall advise the Company that, in its view, the number of securities
requested to be included in such registration by the Holders or any other
persons (including those shares of Common Stock requested by the Company to be
included in such registration) exceeds the largest number (the "Section 2.1 Sale
Number") that can be sold in an orderly manner in such offering within a price
range acceptable to the Initiating Holder, the Company shall include in such
registration:

          (i) all Registrable Securities requested in such registration by
Holders of Registrable Securities; provided, however, that if the number of such
Registrable Securities exceeds the Section 2.1 Sale Number, then the number of
such Registrable Securities (not to exceed the Section 2.1 Sale Number) to be
included in such registration shall be allocated on a pro rata basis among all
Holders requesting that Registrable Securities be included in such registration,
based on the number of Registrable Securities then owned by each Holder
requesting inclusion in relation to the number of Registrable Securities owned
by all Holders requesting inclusion;

          (ii) to the extent that the number of Registrable Securities to be
included by all Holders pursuant to clause (i) of this Section 2.3(a) is less
than the Section 2.1 Sale Number, securities that the Company proposes to
register (up to the Section 2.1 Sale Number); and

          (iii) to the extent that the number of Registrable Securities to be
included by all Holders and the number of securities to be included by the
Company is less than the Section 2.1 Sale Number, any other securities that the
holders thereof propose to register pursuant to the exercise of Additional
Piggyback Rights (up to the Section 2.1 Sale Number); provided that if the
number of securities requested to be registered pursuant to the exercise of
Additional Piggyback Rights exceeds the amount that may be registered, the
number of securities to be included shall be allocated in the manner provided by
the terms of the agreements providing for the Additional Piggyback Rights.

          If, as a result of the proration provisions of this Section 2.3(a),
any Holder shall not be entitled to include all Registrable Securities in a
registration that such Holder has requested be included, such Holder may elect
to withdraw his request to include Registrable Securities in such registration
or may reduce the number requested to be included; provided, however, that (x)
such request must be made in writing prior to the earlier of the execution of
the underwriting agreement or the execution of the custody agreement with
respect to such registration and (y) such withdrawal shall be irrevocable and,
after making such withdrawal, a Holder shall no longer have any right to include
Registrable Securities in the registration as to which such withdrawal was made.


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     (b) If any registration pursuant to Section 2.2 involves an underwritten
offering and the Manager shall advise the Company that, in its view, the number
of securities requested to be included in such registration exceeds the number
(the "Section 2.2 Sale Number") that can be sold in an orderly manner in such
registration within a price range acceptable to the Company, the Company shall
include in such registration:

          (i) all Common Stock or securities convertible into, or exchangeable
or exercisable for, Common Stock that the Company proposes to register for its
own account (the "Company Securities");

          (ii) to the extent that the number of Company Securities is less than
the Section 2.2 Sale Number, the remaining shares to be included in such
registration (up to the Section 2.2 Sale Number) shall be allocated on a pro
rata basis among all Holders timely making a Piggyback Request, based on the
number of Registrable Securities then owned by each Holder requesting inclusion
in relation to the number of Registrable Securities owned by all Holders
requesting inclusion; and

          (iii) to the extent the number of Company Securities plus the number
of Registrable Securities requested to be included by all Holders is less than
the Section 2.2 Sale Number, any other securities that the holders thereof
propose to register pursuant to the exercise of Additional Piggyback Rights
granted to them by the Company pursuant to separate registration rights
agreements after the date hereof (up to the Section 2.2 Sale Number); provided
that if the number of securities requested to be registered pursuant to the
exercise of Additional Piggyback Rights exceeds the amount that may be
registered, the number of securities to be included shall be allocated in the
manner provided by the terms of the agreements providing for the Additional
Piggyback Rights.

     2.4. Registration Procedures. If and whenever the Company is required by
the provisions of this Agreement to use its reasonable best efforts to effect or
cause the registration of any Registrable Securities under the Securities Act as
provided in this Agreement, the Company shall, as expeditiously as possible:

     (a) prepare and file with the SEC a registration statement on an
appropriate registration form of the SEC for the disposition of such Registrable
Securities in accordance with the intended method of disposition thereof, which
form (i) shall be selected by the Company and (ii) shall, in the case of a shelf
registration, be available for the sale of the Registrable Securities by the
selling Holders thereof and such registration statement shall comply as to form
in all material respects with the requirements of the applicable form and
include all financial statements required by the SEC to be filed therewith, and
the Company shall use its reasonable best efforts to cause such registration
statement to become and remain effective for the time period specified below;
provided, however, that before filing a registration statement or prospectus or
any amendments or supplements thereto, or comparable statements under securities
or blue sky laws of any jurisdiction, the Company will furnish to one counsel
for the Holders participating in the planned registration (selected by AIHL, if
AIHL is participating in such registration, or, if AIHL is not participating in
such registration, selected by the Initiating Holder in the case of a
registration pursuant to Section 2.1, or selected by the Major Holder, in the
case of a registration pursuant to Section 2.2) and the underwriters, if any,
copies of all such


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documents proposed to be filed (including all exhibits thereto), which documents
will be subject to the reasonable review and reasonable comment of such counsel
and the underwriters, and the Company shall not file any registration statement
or amendment thereto or any prospectus or supplement thereto to which the
Holders of a majority of the Registrable Securities covered by such registration
statement or the underwriters, if any, shall reasonably object in writing;

     (b) prepare and file with the SEC such amendments and supplements to such
registration statement and the prospectus used in connection therewith as may be
necessary to keep such registration statement effective for such period (which
shall not be required to exceed 180 days in the case of a registration pursuant
to Section 2.1 or 120 days in the case of a registration pursuant to Section
2.2) as any seller of Registrable Securities pursuant to such registration
statement shall request and to comply with the provisions of the Securities Act
with respect to the sale or other disposition of all Registrable Securities
covered by such registration statement in accordance with the intended methods
of disposition by the seller or sellers thereof set forth in such registration
statement;

     (c) furnish, without charge, to each seller of such Registrable Securities
and each underwriter, if any, of the securities covered by such registration
statement such number of copies of such registration statement, each amendment
and supplement thereto (in each case including all exhibits), and the prospectus
included in such registration statement (including each preliminary prospectus)
in conformity with the requirements of the Securities Act, and other documents,
as such seller and underwriter may reasonably request in order to facilitate the
public sale or other disposition of the Registrable Securities owned by such
seller (the Company hereby consenting to the use in accordance with all
applicable law of each such registration statement (or amendment or
post-effective amendment thereto) and each such prospectus (or preliminary
prospectus or supplement thereto) by each such seller of Registrable Securities
and the underwriters, if any, in connection with the offering and sale of the
Registrable Securities covered by such registration statement or prospectus);

     (d) use its reasonable best efforts to register or qualify the Registrable
Securities covered by such registration statement under such other securities or
"blue sky" laws of such jurisdictions as any sellers of Registrable Securities
or any managing underwriter, if any, shall reasonably request, and do any and
all other acts and things which may be reasonably necessary or advisable to
enable such sellers or underwriter, if any, to consummate the disposition of the
Registrable Securities in such jurisdictions, except that in no event shall the
Company be required to qualify to do business as a foreign corporation in any
jurisdiction where it would not, but for the requirements of this paragraph (d),
be required to be so qualified, to subject itself to taxation in any such
jurisdiction or to consent to general service of process in any such
jurisdiction;

     (e) promptly notify each Holder selling Registrable Securities covered by
such registration statement and each managing underwriter, if any: (i) when the
registration statement, any pre-effective amendment, the prospectus or any
prospectus supplement related thereto or post-effective amendment to the
registration statement has been filed and, with respect to the registration
statement or any post-effective amendment, when the same has become effective;
(ii) of any request by the SEC or state


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securities authority for amendments or supplements to the registration statement
or the prospectus related thereto or for additional information; (iii) of the
issuance by the SEC of any stop order suspending the effectiveness of the
registration statement or the initiation of any proceedings for that purpose;
(iv) of the receipt by the Company of any notification with respect to the
suspension of the qualification of any Registrable Securities for sale under the
securities or blue sky laws of any jurisdiction or the initiation of any
proceeding for such purpose; (v) of the existence of any fact of which the
Company becomes aware which results in the registration statement, the
prospectus related thereto or any document incorporated therein by reference
containing an untrue statement of a material fact or omitting to state a
material fact required to be stated therein or necessary to make any statement
therein not misleading; and (vi) if at any time the representations and
warranties contemplated by any underwriting agreement, securities sale
agreement, or other similar agreement, relating to the offering shall cease to
be true and correct in all material respects; and, if the notification relates
to an event described in clause (v), the Company shall promptly prepare and
furnish to each such seller and each underwriter, if any, a reasonable number of
copies of a prospectus supplemented or amended so that, as thereafter delivered
to the purchasers of such Registrable Securities, such prospectus shall not
include an untrue statement of a material fact or omit to state a material fact
required to be stated therein or necessary to make the statements therein in the
light of the circumstances under which they were made not misleading;

     (f) comply with all applicable rules and regulations of the SEC, and make
generally available to its security holders, as soon as reasonably practicable
after the effective date of the registration statement (and in any event within
17 months thereafter), an earnings statement (which need not be audited)
covering the period of at least twelve consecutive months beginning with the
first day of the Company's first calendar quarter after the effective date of
the registration statement, which earnings statement shall satisfy the
provisions of Section 11(a) of the Securities Act and Rule 158 thereunder;

     (g) cause all such Registrable Securities covered by such registration
statement to be listed on the NYSE Arca exchange or such other securities
exchange (including, for this purpose, the Nasdaq National Market) (the NYSE
Arca exchange or such other securities exchange, the "Exchange") on which
similar securities issued by the Company are then listed (if any), if the
listing of such Registrable Securities is then permitted under the rules of such
Exchange;

     (h) enter into such customary agreements (including, if applicable, an
underwriting agreement) and take such other actions as AIHL, if AIHL is
participating in such registration, or, if AIHL is not participating in such
registration, as the Initiating Holder, in the case of a registration pursuant
to Section 2.1, or as the Major Holder, in the case of a registration pursuant
to Section 2.2, shall reasonably request in order to expedite or facilitate the
disposition of such Registrable Securities. The Holders of the Registrable
Securities which are to be distributed by such underwriters shall be parties to
such underwriting agreement and may, at their option, require that the Company
make to and for the benefit of such Holders the representations, warranties and
covenants of the Company which are being made to and for the benefit of such
underwriters and which are of the type customarily provided to institutional
investors in secondary offerings;


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     (i) use its reasonable best efforts to obtain an opinion from the Company's
counsel and a "cold comfort" letter from the Company's independent public
accountants in customary form and covering such matters as are customarily
covered by such opinions and "cold comfort" letters delivered to underwriters in
underwritten public offerings, which opinion and letter shall be reasonably
satisfactory to the underwriter, if any, and to AIHL, if AIHL is participating
in such registration, or, if AIHL is not participating in such registration, to
the Initiating Holder, in the case of a registration pursuant to Section 2.1, or
to the Major Holder, in the case of a registration pursuant to Section 2.2, and
furnish to each Holder participating in the offering and to each underwriter, if
any, a copy of such opinion and letter addressed to such Holder or underwriter;

     (j) deliver promptly to each Holder participating in the offering and each
underwriter, if any, copies of all correspondence between the SEC and the
Company, its counsel or auditors and all memoranda relating to discussions with
the SEC or its staff with respect to the registration statement, other than
those portions of any such memoranda which contain information subject to
attorney-client privilege with respect to the Company, and, upon receipt of such
confidentiality agreements as the Company may reasonably request, make
reasonably available for inspection by any seller of such Registrable Securities
covered by such registration statement, by any underwriter, if any,
participating in any disposition to be effected pursuant to such registration
statement and by any accountant or other agent retained by any such seller or
any such underwriter, all pertinent financial and other records, pertinent
corporate documents and properties of the Company, and cause all of the
Company's officers, directors and employees to supply all information reasonably
requested by any such seller, underwriter, accountant or agent in connection
with such registration statement;

     (k) use its reasonable best efforts to obtain the withdrawal of any order
suspending the effectiveness of the registration statement;

     (l) make reasonably available its employees and personnel and otherwise
provide reasonable assistance to the underwriters (taking into account the needs
of the Company's businesses and the requirements of the marketing process) in
the marketing of Registrable Securities in any underwritten offering;

     (m) promptly prior to the filing of any document which is to be
incorporated by reference into the registration statement or the prospectus
(after the initial filing of such registration statement), provide copies of
such document to counsel (selected pursuant to Section 2.4(a)) for the selling
holders of Registrable Securities and to each managing underwriter, if any, and
make the Company's representatives reasonably available for discussion of such
document and make such changes in such document concerning the selling holders
prior to the filing thereof as such counsel or underwriters may reasonably
request;

     (n) furnish to AIHL, if AIHL is participating in such registration, or, if
AIHL is not participating in such registration, to the Initiating Holder, in the
case of a registration pursuant to Section 2.1, or to the Major Holder, in the
case of a registration pursuant to Section 2.2, and the managing underwriter,
without charge, at least one signed copy, and to each other Holder participating
in the offering, without charge, at


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least one photocopy of a signed copy, of the registration statement and any
post-effective amendments thereto, including financial statements and schedules
included therein; at the request of any Holder participating in the offering, to
furnish to such Holder all documents incorporated therein by reference and all
exhibits (including those incorporated by reference);

     (o) cooperate with the selling Holders of Registrable Securities and the
managing underwriter, if any, to facilitate the timely preparation and delivery
of certificates not bearing any restrictive legends representing the Registrable
Securities to be sold, and cause such Registrable Securities to be issued in
such denominations and registered in such names in accordance with the
underwriting agreement prior to any sale of Registrable Securities to the
underwriters or, if not an underwritten offering, in accordance with the
instructions of the selling Holders of Registrable Securities at least three
business days prior to any sale of Registrable Securities and instruct any
transfer agent and registrar of Registrable Securities to release any stop
transfer orders in respect thereof;

     (p) take all such other commercially reasonable actions as are necessary or
advisable in order to expedite or facilitate the disposition of such Registrable
Securities; and

     (q) take no direct or indirect action prohibited by Regulation M under the
Exchange Act.

          The Company may require as a condition precedent to the Company's
obligations under this Section 2.4 that each seller of Registrable Securities as
to which any registration is being effected furnish the Company such information
regarding such seller and the distribution of such securities as the Company may
from time to time reasonably request provided that such information is necessary
for the Company to consummate such registration and shall be used only in
connection with such registration.

          Each Holder of Registrable Securities agrees that upon receipt of any
notice from the Company of the happening of any event of the kind described in
clause (v) of paragraph (e) of this Section 2.4, such Holder will discontinue
such Holder's disposition of Registrable Securities pursuant to the registration
statement covering such Registrable Securities until such Holder's receipt of
the copies of the supplemented or amended prospectus contemplated by paragraph
(e) of this Section 2.4 and, if so directed by the Company, will deliver to the
Company (at the Company's expense) all copies, other than permanent file copies,
then in such Holder's possession of the prospectus covering such Registrable
Securities that was in effect at the time of receipt of such notice. In the
event the Company shall give any such notice, the applicable period mentioned in
paragraph (b) of this Section 2.4 shall be extended by the number of days during
such period from and including the date of the giving of such notice to and
including the date when each seller of any Registrable Securities covered by
such registration statement shall have received the copies of the supplemented
or amended prospectus contemplated by paragraph (e) of this Section 2.4.


                                       12

<PAGE>

     2.5. Registration Expenses.

     (a) "Expenses" shall mean any and all fees and expenses incident to the
Company's performance of or compliance with this Article 2, including, without
limitation: (i) SEC and National Association of Securities Dealers, Inc.
("NASD") registration and filing fees, (ii) all listing fees and other fees with
respect to the inclusion of securities on the Exchange, (iii) fees and expenses
of compliance with state securities or "blue sky" laws and in connection with
the preparation of a "blue sky" survey, including without limitation, reasonable
fees and expenses of blue sky counsel, (iv) printing and copying expenses, (v)
messenger and delivery expenses, (vi) expenses incurred in connection with any
road show, (vii) fees and disbursements of counsel for the Company, (viii) with
respect to each registration, the fees and disbursements of one counsel for the
selling Holder(s) (selected by AIHL, if AIHL is participating in such
registration, or, if AIHL is not participating in such registration, selected by
the Initiating Holder in the case of a registration pursuant to Section 2.1, or
selected by the Major Holder, in the case of a registration pursuant to Section
2.2), (ix) fees and disbursements of all independent public accountants
(including the expenses of any audit and/or "cold comfort" letter) and fees and
expenses of other persons, including special experts, retained by the Company,
(x) fees and expenses payable to a Qualified Independent Underwriter (as such
term is defined in Rule 2720 of the NASD) to the extent a Qualified Independent
Underwriter is required and (xi) any other fees and disbursements of
underwriters, if any, customarily paid by issuers or sellers of securities
(collectively, "Expenses").

     (b) The Company shall pay all Expenses with respect to any Demand
Registration pursuant to Section 2.1 and any piggyback registrations pursuant to
Section 2.2. For the avoidance of doubt, the Company shall, in the case of all
registrations under this Article 2, be responsible for all of its internal
expenses (including, without limitation, all salaries and expenses of its
officers and employees performing legal or accounting duties).

     (c) Notwithstanding the foregoing, (x) the provisions of this Section 2.5
shall be deemed amended to the extent necessary to cause these expense
provisions to comply with "blue sky" laws of each state in which the offering is
made, (y) in connection with any registration hereunder, each Holder of
Registrable Securities being registered shall pay all underwriting discounts and
commissions attributable to the sale of the number of such Registrable
Securities sold in the offering by such Holder and (z) the Company shall not be
required to pay for the Expenses of any Demand Registration pursuant to Section
2.1 for which a registration proceeding has begun where the request for such
Demand Registration is subsequently withdrawn by the Initiating Holder unless
either (i) the withdrawal is based upon material adverse information concerning
the Company of which the Initiating Holder was not aware at the time such Demand
Registration was first requested or (ii) the Holders of a majority of
Registrable Securities agree to forfeit their right to one Demand Registration
(in which event such right to one Demand Registration shall be forfeited by all
Holders of Registrable Securities). If the Holders are required to pay the
Expenses incurred by the Company in connection with a Demand Registration that
is subsequently withdrawn as described in clause (z) of the immediately
preceding sentence, then such Expenses shall be allocated among the Holders of
Registrable


                                       13

<PAGE>

Securities requesting inclusion of Registrable Securities in such Demand
Registration in an amount proportionate to the total number of Registrable
Securities for which registration was requested; if the Company is required to
pay the Expenses of a withdrawn offering under the circumstances described in
clause (z)(i) of the immediately preceding sentence, then the Holders shall not
forfeit their right to a Demand Registration.

     2.6. Certain Limitations on Registration Rights. In the case of any
registration under Section 2.1 pursuant to an underwritten offering, or in the
case of a registration under Section 2.2 if the Company has determined to enter
into an underwriting agreement in connection therewith, all securities to be
included in such registration shall be subject to an underwriting agreement and
no person may participate in such registration unless such person agrees to sell
such Person's securities on the basis provided therein and completes and
executes all reasonable questionnaires, and other documents (including custody
agreements and powers of attorney) which must be executed in connection
therewith, and provides such other information to the Company or the underwriter
as may be necessary to register such Person's securities.

     2.7. Limitations on Sale or Distribution of Other Securities.

     (a) Each Holder of Registrable Securities agrees that, (i) to the extent
requested in writing by a managing underwriter, if any, of any registration
effected pursuant to Section 2.1 or 2.2, such Holder will agree not to sell,
transfer or otherwise dispose of, including any sale pursuant to Rule 144 under
the Securities Act, any Common Stock, or any other equity security of the
Company or any security convertible into or exchangeable or exercisable for any
equity security of the Company (other than as part of such underwritten public
offering) during the time period reasonably requested by the managing
underwriter, not to exceed 180 days (a "Lock-up"); provided, however, that the
terms of the Lock-up shall be substantially similar to the terms of the lock-up
agreement executed and delivered by AIHL in connection with the IPO; provided,
further, that no Holder shall be required to be subject to a Lock-up unless the
Company and its executive officers and directors are subject to a substantially
similar provision (except that the Company may effect any sale or distribution
of any such securities pursuant to a registration on Form S-4 (if reasonably
acceptable to such managing underwriter) or Form S-8, or any successor or
similar form which is then in effect or upon the conversion, exchange or
exercise of any then outstanding Common Stock Equivalent). The Company agrees to
use its reasonable best efforts to cause each holder of any equity security or
any security convertible into or exchangeable or exercisable for any equity
security of the Company sold or issued by the Company at any time hereafter
other than in a public offering to agree to be bound to a substantially similar
Lock-up in the event of an underwritten registration pursuant to Section 2.1 or
2.2.

     (b) The Company hereby agrees that, if it shall previously have received a
request for registration (other than a shelf registration) pursuant to Section
2.1 or 2.2, and if such previous registration shall not have been withdrawn or
abandoned, the Company shall not sell, transfer, or otherwise dispose of, any
Common Stock, or any other equity security of the Company or any security
convertible into or exchangeable or exercisable for any equity security of the
Company (other than as part of such underwritten public


                                       14

<PAGE>

offering, common stock issued in connection with the acquisition of a business
or assets, a registration on Form S-4 or Form S-8 or any successor or similar
form which is then in effect or upon the conversion, exchange or exercise of any
then outstanding Common Stock Equivalent), until a period of 90 days shall have
elapsed from the effective date of such registration or such longer period (not
to exceed 180 days) as each Holder of Registrable Securities is required to
agree to pursuant to Section 2.7(a).

     2.8. No Required Sale. Nothing in this Agreement shall be deemed to create
an independent obligation on the part of any Holder to sell any Registrable
Securities pursuant to any effective registration statement.

     2.9. Indemnification.

     (a) In the event of any registration of any securities of the Company under
the Securities Act pursuant to this Article 2, the Company will, and hereby
does, indemnify and hold harmless, to the fullest extent permitted by law, each
Holder of Registrable Securities, its directors, officers, fiduciaries,
employees and stockholders or general and limited partners (and the directors,
officers, employees and stockholders thereof), each other Person who
participates as an underwriter or a Qualified Independent Underwriter, if any,
in the offering or sale of such securities, each officer, director, employee,
stockholder, fiduciary, managing director, agent, affiliates, consultants,
representatives, successors, assigns or partner of such underwriter or Qualified
Independent Underwriter, and each other Person, if any, who controls such seller
or any such underwriter within the meaning of the Securities Act, against any
and all losses, claims, damages or liabilities, joint or several, actions or
proceedings (whether commenced or threatened) and expenses (including reasonable
fees of counsel and any amounts paid in any settlement effected with the
Company's consent, which consent shall not be unreasonably withheld or delayed)
to which each such indemnified party may become subject under the Securities Act
or otherwise in respect thereof (collectively, "Claims"), insofar as such Claims
arise out of or are based upon (i) any untrue statement or alleged untrue
statement of a material fact contained in any registration statement under which
such securities were registered under the Securities Act or the omission or
alleged omission to state therein a material fact required to be stated therein
or necessary to make the statements therein not misleading, (ii) any untrue
statement or alleged untrue statement of a material fact contained in any
preliminary, final or summary prospectus or any amendment or supplement thereto,
together with the documents incorporated by reference therein, or the omission
or alleged omission to state therein a material fact required to be stated
therein or necessary in order to make the statements therein, in the light of
the circumstances under which they were made, not misleading, or (iii) any
violation by the Company of any federal, state or common law rule or regulation
applicable to the Company and relating to action required of or inaction by the
Company in connection with any such registration, and the Company will reimburse
any such indemnified party for any legal or other expenses reasonably incurred
by such indemnified party in connection with investigating or defending any such
Claim as such expenses are incurred; provided, however, that the Company shall
not be liable to any such indemnified party in any such case to the extent such
Claim arises out of or is based upon any untrue statement or alleged untrue
statement of a material fact or omission or alleged omission of a material fact
made in such registration statement or amendment thereof or supplement thereto
or


                                       15

<PAGE>

in any such prospectus or any preliminary, final or summary prospectus in
reliance upon and in conformity with written information furnished to the
Company by or on behalf of such indemnified party specifically for use therein.
Such indemnity and reimbursement of expenses shall remain in full force and
effect regardless of any investigation made by as on behalf of such indemnified
party and shall survive the transfer of such securities by such seller.

     (b) Each Holder of Registrable Securities that are included in the
securities as to which any registration under Section 2.1 or 2.2 is being
effected (and, if the Company requires as a condition to including any
Registrable Securities in any registration statement filed in accordance with
Section 2.1 or 2.2, any underwriter and Qualified Independent Underwriter, if
any) shall, severally and not jointly, indemnify and hold harmless (in the same
manner and to the same extent as set forth in paragraph (a) of this Section 2.9)
to the extent permitted by law the Company, its officers and directors, each
Person controlling the Company within the meaning of the Securities Act and all
other prospective sellers and their respective directors, officers, fiduciaries,
managing directors, employees, agents, affiliates, consultants, representatives,
successors, assigns, general and limited partners, stockholders and respective
controlling Persons with respect to any untrue statement or alleged untrue
statement of any material fact in, or omission or alleged omission of any
material fact from, such registration statement, any preliminary, final or
summary prospectus contained therein, or any amendment or supplement thereto, if
such statement or alleged statement or omission or alleged omission was made in
reliance upon and in conformity with written information furnished to the
Company or its representatives by or on behalf of such Holder or underwriter or
Qualified Independent Underwriter, if any, specifically for use therein and
reimburse such indemnified party for any legal or other expenses reasonably
incurred in connection with investigating or defending any such Claim as such
expenses are incurred; provided, however, that the aggregate amount which any
such Holder shall be required to pay pursuant to this Section 2.9(b) and
Sections 2.9(c) and (e) shall in no case be greater than the amount of the net
proceeds received by such person upon the sale of the Registrable Securities
pursuant to the registration statement giving rise to such claim. Such indemnity
and reimbursement of expenses shall remain in full force and effect regardless
of any investigation made by or on behalf of such indemnified party and shall
survive the transfer of such securities by such Holder.

     (c) Indemnification similar to that specified in the preceding paragraphs
(a) and (b) of this Section 2.9 (with appropriate modifications) shall be given
by the Company and each seller of Registrable Securities with respect to any
required registration or other qualification of securities under any state
securities and "blue sky" laws.

     (d) Any person entitled to indemnification under this Agreement shall
notify promptly the indemnifying party in writing of the commencement of any
action or proceeding with respect to which a claim for indemnification may be
made pursuant to this Section 2.9, but the failure of any indemnified party to
provide such notice shall not relieve the indemnifying party of its obligations
under the preceding paragraphs of this Section 2.9, except to the extent the
indemnifying party is materially prejudiced thereby and shall not relieve the
indemnifying party from any liability which it may have to any


                                       16

<PAGE>

indemnified party otherwise than under this Article 2. In case any action or
proceeding is brought against an indemnified party and it shall notify the
indemnifying party of the commencement thereof, the indemnifying party shall be
entitled to participate therein and, unless in the reasonable opinion of outside
counsel to the indemnified party a conflict of interest between such indemnified
and indemnifying parties may exist in respect of such claim, to assume the
defense thereof jointly with any other indemnifying party similarly notified, to
the extent that it chooses, with counsel reasonably satisfactory to such
indemnified party, and after notice from the indemnifying party to such
indemnified party that it so chooses, the indemnifying party shall not be liable
to such indemnified party for any legal or other expenses subsequently incurred
by such indemnified party in connection with the defense thereof other than
reasonable costs of investigation; provided, however, that (i) if the
indemnifying party fails to take reasonable steps necessary to defend diligently
the action or proceeding within 20 days after receiving notice from such
indemnified party that the indemnified party believes it has failed to do so; or
(ii) if such indemnified party who is a defendant in any action or proceeding
which is also brought against the indemnifying party reasonably shall have
concluded that there may be one or more legal defenses available to such
indemnified party which are not available to the indemnifying party; or (iii) if
representation of both parties by the same counsel is otherwise inappropriate
under applicable standards of professional conduct, then, in any such case, the
indemnified party shall have the right to assume or continue its own defense as
set forth above (but with no more than one firm of counsel (selected by AIHL, if
AIHL has participated in the applicable registration and is an indemnified
party, or, if AIHL has not participated in the applicable registration or is not
an indemnified party, selected by the Initiating Holder in the case of a
registration pursuant to Section 2.1, or selected by the Major Holder, in the
case of a registration pursuant to Section 2.2) for all indemnified parties in
each jurisdiction, except to the extent any indemnified party or parties
reasonably shall have concluded that there may be legal defenses available to
such party or parties which are not available to the other indemnified parties
or to the extent representation of all indemnified parties by the same counsel
is otherwise inappropriate under applicable standards of professional conduct)
and the indemnifying party shall be liable for any expenses therefor. No
indemnifying party shall, without the written consent of the indemnified party,
effect the settlement or compromise of, or consent to the entry of any judgment
with respect to, any pending or threatened action or claim in respect of which
indemnification or contribution may be sought hereunder (whether or not the
indemnified party is an actual or potential party to such action or claim)
unless such settlement, compromise or judgment (A) includes an unconditional
release of the indemnified party from all liability arising out of such action
or claim and (B) does not include a statement as to or an admission of fault,
culpability or a failure to act, by or on behalf of any indemnified party.

     (e) If for any reason the foregoing indemnity is unavailable or is
insufficient to hold harmless an indemnified party under Section 2.9(a), (b) or
(c), then each indemnifying party shall contribute to the amount paid or payable
by such indemnified party as a result of any Claim in such proportion as is
appropriate to reflect the relative fault of the indemnifying party, on the one
hand, and the indemnified party, on the other hand, with respect to such
offering of securities. The relative fault shall be determined by reference to,
among other things, whether the untrue or alleged untrue statement of a material
fact or the omission or alleged omission to state a material fact relates to


                                       17

<PAGE>

information supplied by the indemnifying party or the indemnified party and the
parties' relative intent, knowledge, access to information and opportunity to
correct or prevent such untrue statement or omission. If, however, the
allocation provided in the second preceding sentence is not permitted by
applicable law, then each indemnifying party shall contribute to the amount paid
or payable by such indemnified party in such proportion as is appropriate to
reflect not only such relative faults but also the relative benefits of the
indemnifying party and the indemnified party as well as any other relevant
equitable considerations. The parties hereto agree that it would not be just and
equitable if contributions pursuant to this Section 2.9(e) were to be determined
by pro rata allocation or by any other method of allocation which does not take
account of the equitable considerations referred to in the preceding sentences
of this Section 2.9(e). The amount paid or payable in respect of any Claim shall
be deemed to include any legal or other expenses reasonably incurred by such
indemnified party in connection with investigating or defending any such Claim.
No person guilty of fraudulent misrepresentation (within the meaning of Section
11(f) of the Securities Act) shall be entitled to contribution from any person
who was not guilty of such fraudulent misrepresentation. Notwithstanding
anything in this section 2.9(e) to the contrary, no indemnifying party (other
than the Company) shall be required pursuant to this section 2.9(e) to
contribute any amount in excess of the net proceeds received by such
indemnifying party from the sale of Registrable Securities in the offering to
which the losses, claims, damages or liabilities of the indemnified parties
relate, less the amount of any indemnification payment made by such indemnifying
party pursuant to Sections 2.9(b) and (c).

     (f) The indemnity agreements contained herein shall be in addition to any
other rights to indemnification or contribution which any indemnified party may
have pursuant to law or contract and shall remain operative and in full force
and effect regardless of any investigation made or omitted by or on behalf of
any indemnified party and shall survive the transfer of the Registrable
Securities by any such party.

     (g) The indemnification and contribution required by this Section 2.9 shall
be made by periodic payments of the amount thereof during the course of the
investigation or defense, as and when bills are received or expense, loss,
damage or liability is incurred.

3. Underwritten Offerings.

     3.1. Requested Underwritten Offerings. If requested by the underwriters for
any underwritten offering by the Holders pursuant to a registration requested
under Section 2.1, the Company shall enter into a customary underwriting
agreement with the underwriters. Such underwriting agreement shall be
satisfactory in form and substance to the Initiating Holder and shall contain
such representations and warranties by, and such other agreements on the part
of, the Company and such other terms as are generally prevailing in agreements
of that type, including, without limitation, indemnities and contribution
agreements on substantially the same terms as those contained herein. Any Holder
participating in the offering shall be a party to such underwriting agreement
and may, at its option, require that any or all of the representations and
warranties by, and the other agreements on the part of, the Company to and for
the benefit of such underwriters shall also be made to and for the


                                       18

<PAGE>

benefit of such Holder and that any or all of the conditions precedent to the
obligations of such underwriters under such underwriting agreement be conditions
precedent to the obligations of such Holder; provided, however, that the Company
shall not be required to make any representations or warranties with respect to
written information specifically provided by a selling Holder for inclusion in
the registration statement. Such underwriting agreement shall also contain such
representations and warranties by the participating Holders with respect to
title and ownership of shares as are customary in agreements of that type.

     3.2. Piggyback Underwritten Offerings. In the case of a registration
pursuant to Section 2.2 hereof, if the Company shall have determined to enter
into an underwriting agreement in connection therewith, all of the Holders'
Registrable Securities to be included in such registration shall be subject to
such underwriting agreement. Any Holder participating in such registration may,
at its option, require that any or all of the representations and warranties by,
and the other agreements on the part of, the Company to and for the benefit of
such underwriters shall also be made to and for the benefit of such Holder and
that any or all of the conditions precedent to the obligations of such
underwriters under such underwriting agreement be conditions precedent to the
obligations of such Holder. Such underwriting agreement shall also contain such
representations and warranties by the participating Holders as are customary in
agreements of that type, on substantially the same terms as those contained
herein.

4. General.

     4.1. Rule 144. If the Company shall have filed a registration statement
pursuant to the requirements of Section 12 of the Exchange Act or a registration
statement pursuant to the requirements of the Securities Act in respect of the
Common Stock or securities of the Company convertible into or exchangeable or
exercisable for Common Stock, the Company covenants that (i) so long as it
remains subject to the reporting provisions of the Exchange Act, it will timely
file the reports required to be filed by it under the Securities Act or the
Exchange Act (including, but not limited to, the reports under Sections 13 and
15(d) of the Exchange Act referred to in subparagraph (c)(1) of Rule 144 under
the Securities Act), and (ii) will take such further action as any Holder of
Registrable Securities may reasonably request, all to the extent required from
time to time to enable such Holder to sell Registrable Securities without
registration under the Securities Act within the limitation of the exemptions
provided by (A) Rule 144 under the Securities Act, as such Rule may be amended
from time to time, or (B) any similar rule or regulation hereafter adopted by
the SEC. Upon the request of any Holder of Registrable Securities, the Company
will deliver to such Holder a written statement as to whether it has complied
with such requirements.

     4.2. Nominees for Beneficial Owners. If Registrable Securities are held by
a nominee for the beneficial owner thereof, the beneficial owner thereof may, at
its option, be treated as the Holder of such Registrable Securities for purposes
of any request or other action by any Holder or Holders of Registrable
Securities pursuant to this Agreement (or any determination of any number or
percentage of shares constituting Registrable Securities held by any Holder or
Holders of Registrable


                                       19

<PAGE>

Securities contemplated by this Agreement), provided that the Company shall have
received assurances reasonably satisfactory to it of such beneficial ownership.

     4.3. Amendments and Waivers. The terms and provisions of this Agreement may
be modified or amended, or any of the provisions hereof waived, temporarily or
permanently, pursuant to the written consent of the Company and AIHL (without
the consent of the other Holders of Registrable Securities); provided, however,
that if AIHL no longer holds any Registrable Securities, then the consent of the
Holder or Holders of a majority of the then outstanding Registrable Securities
(and not AIHL) would be required (and such consent of the Holder or Holders of a
majority of the then outstanding Registrable Securities would be binding upon
all Holders of then outstanding Registrable Securities).

     4.4. Notices. All notices, requests and other communications pursuant to
this Agreement shall be in writing and shall be deemed to have been duly given,
if delivered in person or by courier, or sent by express, registered or
certified mail, postage prepaid, to AIHL or to the Company at the address set
forth below:

     (a)  If to AIHL, to:

          Alleghany Insurance Holdings LLC
          c/o Alleghany Corporation
          7 Times Square Tower
          17th Floor
          New York, NY 10036
          Attention: Chairman

          with a copy to:

          Alleghany Corporation
          7 Times Square Tower
          17th Floor
          New York, NY 10036
          Attention: General Counsel

     (b)  If to the Company, to:

          Darwin Professional Underwriters, Inc.
          9 Farm Springs Road
          Farmington, Connecticut 06032
          Attention: Chairman

          with a copy to:

          Darwin Professional Underwriters, Inc.
          9 Farm Springs Road
          Farmington, Connecticut 06032
          Attention: General Counsel


                                       20

<PAGE>

Any party may, by written notice to the other party hereto, change the address
to which notices to such party are to be delivered or mailed.

     4.5. Miscellaneous.

     (a) This Agreement shall be binding upon and inure to the benefit of and be
enforceable by the parties hereto and the respective successors, personal
representatives and assigns of the parties hereto, whether so expressed or not.
If any Person shall acquire Registrable Securities from any Holder, in any
manner, whether by operation of law or otherwise, such transferee shall promptly
notify the Company and such Registrable Securities acquired from such Holder
shall be held subject to all of the terms of this Agreement, and by taking and
holding such Registrable Securities such Person shall be entitled to receive the
benefits of and be conclusively deemed to have agreed to be bound by and to
perform all of the terms and provisions of this Agreement. If the Company shall
so request, any such successor or assign shall agree in writing to acquire and
hold the Registrable Securities acquired from such Holder subject to all of the
terms hereof. If any Holder shall acquire additional Registrable Securities,
such Registrable Securities shall be subject to all of the terms, and entitled
to all the benefits, of this Agreement.

     (b) This Agreement (with the documents referred to herein or delivered
pursuant hereto) embodies the entire agreement and understanding between the
parties hereto and supersedes all prior agreements and understandings relating
to the subject matter hereof.

     (c) The headings in this Agreement are for convenience of reference only
and shall not limit or otherwise affect the meaning hereof. All section
references are to this Agreement unless otherwise expressly provided.

     (d) This Agreement may be executed in any number of counterparts, each of
which shall be an original, but all of which together shall constitute one
instrument.

     (e) Any term or provision of this Agreement which is invalid or
unenforceable in any jurisdiction shall, as to such jurisdiction, be ineffective
to the extent of such invalidity or unenforceability without rendering invalid
or unenforceable the remaining terms and provisions of this Agreement or
affecting the validity or enforceability of any of the terms or provisions of
this Agreement in any other jurisdiction.

     (f) The parties hereto acknowledge that there would be no adequate remedy
at law if any party fails to perform any of its obligations hereunder, and
accordingly agree that each party, in addition to any other remedy to which it
may be entitled at law or in equity, shall be entitled to injunctive relief,
including specific performance, to enforce such obligations without the posting
of any bond, and, if any action should be brought in equity to enforce any of
the provisions of this Agreement, none of the parties hereto shall raise the
defense that there is an adequate remedy at law.

     (g) Each party hereto shall do and perform or cause to be done and
performed all such further acts and things and shall execute and deliver all
such other agreements, certificates, instruments, and documents as any other
party hereto reasonably may request


                                       21

<PAGE>

in order to carry out the intent and accomplish the purposes of this Agreement
and the consummation of the transactions contemplated hereby.

     4.6. No Inconsistent Agreements. Without the prior written consent of AIHL,
if AIHL holds Registrable Securities, or the consent of the Holder of a majority
of the then outstanding Registrable Securities, if AIHL no longer holds any
Registrable Securities, neither the Company nor any Holder will, on or after the
date of this Agreement, enter into any agreement with respect to its securities
which is inconsistent with the rights granted in this Agreement or otherwise
conflicts with the provisions hereof. The Company further agrees that if any
other registration rights agreement entered into after the date of this
Agreement with respect to any of its securities contains terms which are more
favorable to, or less restrictive on, the other party thereto than the terms and
conditions contained in this Agreement are (insofar as they are applicable) to
AIHL and its transferees, then the terms and conditions of this Agreement shall
immediately be deemed to have been amended without further action by the Company
or any of the holders of Registrable Securities so that AIHL and its transferees
shall be entitled to the benefit of any such more favorable or less restrictive
terms or conditions.

     4.7. Termination. The registration rights hereunder shall cease to apply to
any particular Registrable Securities when (w) a registration statement with
respect to the sale of such Registrable Securities shall have become effective
under the Securities Act and such Registrable Securities shall have been
disposed of in accordance with such registration statement; (x) such Registrable
Securities shall have been sold to the public pursuant to Rule 144 under the
Securities Act (or any successor provision); (y) such Registrable Securities
shall have been otherwise transferred, new certificates for them not bearing a
legend restricting further transfer shall have been delivered by the Company and
subsequent public distribution of them shall not require registration or
qualification of them under the Securities Act or any similar state law then in
force; or (z) such Registrable Securities shall have ceased to be outstanding.

     4.8. Governing Law; Consent to Jurisdiction; Waiver of Jury Trial. This
Agreement shall be governed by and construed in accordance with the laws of the
State of Delaware, regardless of the laws that might otherwise govern under
applicable principles of conflicts of laws thereof. Each of the parties hereby
irrevocably and unconditionally consents to submit to the exclusive jurisdiction
of the courts of the state and federal courts located in the State of Delaware
for the purposes of enforcing this Agreement. The parties shall take such
actions as are within their control to cause any matter contemplated hereby to
be assigned to the Chancery Court of the State of Delaware. In any action, suit
or other proceeding, each of the parties hereto irrevocably and unconditionally
waives and agrees not to assert by way of motion, as a defense or otherwise any
claim that it is not subject to the jurisdiction of the above courts, that such
action or suit is brought in an inconvenient forum or that the venue of such
action, suit or other proceeding is improper. Each of the parties hereto also
agrees that any final and unappealable judgment against a party hereto in
connection with any action, suit or other proceeding shall be conclusive and
binding on such party and that such award or judgment may be enforced in any
court of competent jurisdiction, either within or outside of the United States.
A certified or exemplified copy of such award or


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<PAGE>

judgment shall be conclusive evidence of the fact and amount of such award or
judgment. Each of the parties hereto hereby irrevocably waives any and all right
to trial by jury in any legal proceeding arising out of or related to this
Agreement or the transactions contemplated hereby.

          IN WITNESS WHEREOF, the parties have executed this Registration Rights
Agreement or caused their duly authorized officers to execute this Registration
Rights Agreement as of the date first above written.

                                         ALLEGHANY INSURANCE HOLDINGS LLC


                                         By: /s/ WESTON M. HICKS
                                             -----------------------------------
                                         Name: Weston M. Hicks
                                         Title: Chief Executive Officer


                                         DARWIN PROFESSIONAL UNDERWRITERS, INC.


                                         By: /s/ STEPHEN SILLS
                                             -----------------------------------
                                         Name: Stephen Sills
                                         Title: President and CEO


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