________________________________________
TRINITY ACQUISITION PLC
Issuer
WILLIS GROUP HOLDINGS PUBLIC LIMITED COMPANY
Holdings
WILLIS NETHERLANDS HOLDINGS B.V.
WILLIS INVESTMENT UK HOLDINGS LIMITED
TA I LIMITED
TA II LIMITED
TA III LIMITED
TA IV LIMITED
WILLIS GROUP LIMITED
WILLIS NORTH AMERICA INC.
the Other Guarantors
and
THE BANK OF NEW YORK MELLON
Trustee

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Third Supplemental Indenture
Dated as of March 18, 2010
to the
Indenture
Dated as of March 6, 2009

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Supplemental Indenture (this “Third Supplemental Indenture”), dated as of
March 18, 2010, among TRINITY ACQUISITION PLC (the “Issuer”), WILLIS NETHERLANDS
HOLDINGS B.V., WILLIS INVESTMENT UK HOLDINGS LIMITED, TA I LIMITED, TA II
LIMITED, TA III LIMITED, TA IV LIMITED, WILLIS GROUP LIMITED and WILLIS NORTH
AMERICA INC. (the “Other Guarantors”), and WILLIS GROUP HOLDINGS PUBLIC LIMITED
COMPANY (“Holdings”) and THE BANK OF NEW YORK MELLON, as trustee (the
“Trustee”).

W I T N E S S E T H

WHEREAS, each of the Issuer, Holdings, the Other Guarantors and the Trustee are
parties to an indenture (the “Base Indenture”), dated as of March 6, 2009, as
supplemented by the First Supplemental Indenture, dated as of November 18, 2009,
and the Second Supplemental Indenture, dated as of December 31, 2009 (together,
the “Indenture”) providing for the issuance of $500,000,000 aggregate principal
amount of 12.875% Senior Notes due 2016 (the “Notes”);

WHEREAS, Section 9.02(a) of the Indenture provides that the Issuer, the
Guarantors and the Trustee may amend or supplement certain provisions of the
Indenture, the Notes and the Guarantees with the consent of the Required Holders
voting as a single class and upon the delivery of certain documentation to the
Trustee; and

WHEREAS, the Trustee is authorized to execute and deliver this Third
Supplemental Indenture.

NOW THEREFORE, in consideration of the foregoing and for other good and valuable
consideration, the receipt of which is hereby acknowledged, the parties mutually
covenant and agree as follows:

(1) Capitalized Terms. Capitalized terms used herein without definition shall
have the meanings assigned to them in the Indenture.

(2) Amendments to Indenture. Subject to the conditions set forth in Article 9 of
the Indenture, the Indenture is amended as set forth in this Section 2.

(a) Section 1.01, clause (9) of the definition of “Permitted Investment” is
restated in its entirety, as follows:

“Investments by WSI in any ILS or equity, equity-linked or debt securities in
the ordinary course of WSI’s business for the purpose of  (i)  placing,
reselling or otherwise distributing such securities in connection with private
placements or registered offerings in an aggregate amount not to exceed
$300,000,000 at any one time outstanding; or (ii) trading such securities in
agency transactions and otherwise, other than for its own account, in each
case as authorized by the Financial Industry Regulatory Authority;”

(3) Conditions Precedent to Effectiveness. This Third Supplemental Indenture
shall become effective upon the satisfaction of each of the conditions precedent
set forth in this Section 3:

(a) The Trustee shall have received evidence of consent of the Required Holders
to amend the Indenture pursuant to Section 9.02(a) of the Indenture along with
the documents described in Section 7.02(b), Section 9.02(a), Section 9.05 and
Section 12.03 of the Indenture;

(b) The Trustee shall have received executed counterparts of this Third
Supplemental Indenture from all of the parties hereto, and the documents
identified; and

(4) Execution and Delivery. Each of the undersigned agrees that the Third
Supplemental Indenture shall remain in full force and effect notwithstanding the
absence of the endorsement of any notation of such Supplemental Indenture on the
Notes.

(5) Governing Law. THIS THIRD SUPPLEMENTAL INDENTURE WILL BE GOVERNED BY AND
CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK.

(6) Counterparts. The parties may sign any number of copies of this Third
Supplemental Indenture. Each signed copy shall be an original, but all of them
together represent the same agreement.

(7) Effect of Headings. The section headings herein are for convenience only and
shall not affect the construction hereof.

(8) The Trustee. The Trustee shall not be responsible in any manner whatsoever
for or in respect of the validity or sufficiency of this Third Supplemental
Indenture or for or in respect of the recitals contained herein, all of which
recitals are made solely by the other parties hereto.

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IN WITNESS WHEREOF, the parties hereto have caused this Third Supplemental
Indenture to be duly executed, all as of the date first above written.

      TRINITY ACQUISITION PLC By: /s/ Grahame Millwater
 

Name:
Title:
  Grahame Millwater
Director

     

      WILLIS NETHERLANDS HOLDINGS B.V. By: /s/ Adriaan Konijnendijk
 

Name:
  Adriaan Konijnendijk

    Title: Managing Director

WILLIS INVESTMENT UK HOLDINGS LIMITED

      TA I LIMITED     TA II LIMITED     TA III LIMITED     TA IV LIMITED    
WILLIS GROUP LIMITED By: /s/ Grahame Millwater
 

Name:
  Grahame Millwater

    Title: Director

      WILLIS NORTH AMERICA INC. By: /s/ Derek Smyth
 

Name:
Title:
  Derek Smyth
Chief Financial Officer

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    WILLIS GROUP HOLDINGS PUBLIC LIMITED COMPANY

     
PRESENT when
the common seal of
WILLIS GROUP
HOLDINGS PUBLIC
LIMITED COMPANY was
affixed to this
Deed:-
 

/s/ Nicole Napolitano—
—
NICOLE NAPOLITANO
MEMBER OF SEALING COMMITTEE
 
 

 
  /s/ Shaun Bryant—
 
   
 
  SHAUN BRYANT
MEMBER OF SEALING COMMITTEE

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    THE BANK OF NEW YORK MELLON, as Trustee

      By: /s/ Timothy E. Burke
 

Name:
Title:
  Timothy E. Burke
Vice President

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