<PAGE>


                                                                   EXHIBIT 10.20

                    AMENDMENT NO. 1 TO VOTING TRUST AGREEMENT

         THIS Amendment No. 1 (this "Amendment"), dated _____________, 2002 to
the VOTING TRUST AGREEMENT (the "Agreement") made the 17th day of December 1999,
by and among Allied Healthcare Group Limited (formerly known as Transworld
Holdings (UK) Limited), a company incorporated in England and Wales with
registered number 3370146 ("UK Parent"), Transworld Healthcare (UK) Limited, a
company incorporated in England and Wales with registered number 3370146 ("TW
UK"), Transworld Healthcare, Inc., a New York corporation ("US Parent"), Triumph
Partners III, L.P., a Delaware limited partnership ("Triumph"), and Richard
Green (hereinafter sometimes referred to, together with his successor in trust,
as the "Trustee"). UK Parent and US Parent are hereinafter referred to
collectively as the "Initial Shareholders." US Parent, UK Parent and TW UK are
hereinafter referred to collectively as the "Corporate Group."

                               W I T N E S S E T H

         WHEREAS, on December 17, 1999, the parties entered into the Agreement
to provide a mechanism for exercising the voting rights attributable to the
outstanding ordinary shares of TW UK and UK Parent owned by the Initial
Shareholders so as to give effect to the commercial understanding between the
Purchasers (as defined in that certain Securities Purchase Agreement (the
"Purchase Agreement"), dated as of December 17, 1999, as amended, among UK
Parent, TW UK, the Purchasers and US Parent), on the one hand, and the Initial
Shareholders, on the other hand, with respect to the exercise of control over
the business and policies of TW UK and UK Parent and other matters of corporate
governance as between majority and minority shareholders;

         WHEREAS, as of the date hereof, the US Parent has approved the
reorganization of the Corporate Group, pursuant to which TW UK shall become a
wholly-owned subsidiary of UK Parent, which is and shall remain a wholly-owned
subsidiary of US Parent (the "Reorganization") in accordance with that certain
Master Reorganization Agreement, dated as of April 24, 2002 by an among the
Corporate Group and the Investors named therein (the "Reorganization
Agreement"); and

         WHEREAS, in connection with the Reorganization, Triumph shall acquire
shares of US Parent Preferred Stock and it is the intention of the parties that
for so long as such Preferred Stock (or any US Parent Common Stock issuable upon
conversion thereof) remains outstanding, Triumph is to be afforded certain
amended voting rights as fully described herein.

         NOW, THEREFORE, in consideration of the mutual covenants herein
contained and for other good, valuable and sufficient consideration, the receipt
of which is hereby acknowledged, the parties hereto promise, covenant, undertake
and agree as follows:

         1. Definitions. Capitalized terms used in the Agreement and not
otherwise defined shall have the meanings ascribed thereto in the Certificate of
Amendment to the Certificate of Designations of Series A Convertible Preferred
Stock of the US Parent (the "Preferred Stock Certificate"), rather than the
Purchase Agreement.

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         2. Transfer of Securities. Effective hereby, the following shall be
substituted in its entirety for clause (iii) of the second paragraph of Section
3 of the Agreement: Intentionally Omitted.

         3. Withdrawal of Shares from Voting Trust.

              (a) Effective hereby, the following shall be substituted in its
entirety for paragraph (a) of Section 4 of the Agreement:

              "at any time after the fifteenth anniversary of the date hereof,
         provided that all obligations of US Parent, UK Parent and TW UK arising
         from (i) a conversion of the Series A Preferred Stock, (ii) the
         exercise of the Holders' Redemption with respect to the Series A
         Preferred Stock, (iii) the Mirror Preferred Stock, (iv) the Mirror
         Notes or (v) the Mirror PIK Notes, shall have been duly and fully
         satisfied."

              (b) Effective hereby, the following shall be substituted in its
entirety for paragraph (b) of Section 4 of the Agreement: Intentionally Omitted.

         4. Rights, Powers and Duties of the Trustee; Obligations of Initial
Shareholders. Effective hereby, the following shall be substituted in its
entirety for paragraph (f) of Section 5 of the Agreement:

              "Subject to the requirements of Applicable Law, each of the
         Initial Shareholders shall instruct the Trustee to vote their Shares
         (whether at a general or extraordinary meeting of shareholders or by
         consent in lieu of a meeting of shareholders) and where appropriate to
         give effect to such matters, shall convene any necessary shareholders
         meeting for the purpose of passing (and, unless pursuant to an amending
         resolution required for the purpose of authorizing and giving effect to
         the Holders' Redemption of Series A Preferred Stock pursuant to the
         Preferred Stock Certificate and Article VIII of the Purchase Agreement,
         not revoking) such resolutions as may be required by Applicable Law to
         approve or authorize any purchase of securities pursuant to Article
         VIII of the Purchase Agreement, including without limitation, any
         special resolutions required under Sections 165 and/or 171 of the
         Companies Act 1985."

         5. Voting by the Trustee.

              (a) Effective hereby, the following shall be substituted in its
entirety for paragraph (a)(iii) of Section 6 of the Agreement: Intentionally
Omitted.

              (b) Effective hereby, the following shall be substituted in its
entirety for the definition of "Put Breach" in paragraph (b) of Section 6 the
Agreement:

         "Put Breach" means, with respect to any of (i) a Holders' Redemption of
Series A Preferred Stock , (ii) a redemption or repayment of Mirror Preferred
Stock or (iii) a redemption or repayment of Mirror Notes and/or Mirror PIK Notes
(each a "Put"), the failure of US Parent,

                                        2
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UK Parent and/or TW UK to fulfill their respective obligations in all material
respects in the manner and at the time provided in the Preferred Stock
Certificate, the charter of UK Parent (including the terms of the Mirror
Preferred Stock) or the Purchase Agreement, provided that a failure by UK Parent
so to fulfill its obligations shall not be deemed to be a Put Breach unless TW
UK shall also have failed to fulfill its obligations on the corresponding Put.

              (c) Effective hereby, the following shall be substituted in its
entirety for clause (iv) of paragraph (c) of Section 6 of the Agreement:

              "(iv) Up to four additional persons who (except as provided below)
         are neither partners, directors, agents, Affiliates, officers or
         employees of any of US Parent, Triumph or their Affiliates, nor
         officers or employees of UK Parent or TW UK or any of its Subsidiaries
         (the "Independent Directors"), who will be nominated with the
         affirmative vote of a majority of the directors then in office
         following the nomination procedure set forth below; provided, however,
         that "independent" directors of US Parent who are neither officers or
         employees of US Parent, UK Parent or TW UK nor Affiliates of Hyperion
         Partners II, L.P., Hyperion TW Fund, L.P., Hyperion TWH Fund LLC,
         Hyperion TWH Fund II LLC or Triumph will be eligible to be nominated as
         Independent Directors pursuant to this Section 6(c);"

              (d) Effective hereby, the following shall be added as clause (v)
of paragraph (c) of Section 6 of the Agreement:

              "(v) the chief operating officer of TW UK (the "TW UK Director"
and, also a "Management Director"), provided that the initial TW UK Director
shall be Sarah Eames;

              (e) Effective hereby, the following shall be substituted in its
entirety for the second subparagraph of paragraph (c) of Section 6 of the
Agreement:

              "If at any time, (i) any of Triumph or the registered holders of
the Voting Trust Certificates shall notify the Trustee and the other parties
hereto of its desire to remove, with or without cause (as defined below), any
director of TW UK or UK Parent previously designated by it pursuant to this
Section 6(c), (ii) either Management Director ceases to be employed as the chief
executive officer or the chief operating officer, as the case may be, of TW UK,
or (iii) the directors (other than the director who is proposed to be removed)
then in office unanimously agree to request the removal of an Independent
Director, then the Trustee agrees to vote all of the Shares so as to remove such
director. If at any time, any of the Investor Director, the Parent Director or
the TW UK Director ceases to serve on the Board of Directors of TW UK or UK
Parent (whether by reason of death, resignation, removal or otherwise), the
party who designated such director shall be entitled to designate a successor
director to fill the vacancy created thereby on the terms and subject to the
conditions of this Section 6(c) and the Trustee shall vote all of the Shares so
as to elect any such director. If at any time an Independent Director ceases to
serve on the Board of Directors of TW UK or UK Parent (whether by reason of
death, resignation, removal or otherwise), a successor director shall be
designated and elected on the terms and subject to the conditions provided in
this Section 6(c)."

                                       3
<PAGE>

                    AMENDMENT NO. 1 TO VOTING TRUST AGREEMENT
                             COMPANY SIGNATURE PAGE

         IN WITNESS WHEREOF, the parties have executed this Amendment No. 1 to
Voting Trust Agreement as a deed as of the date first above written.

                                       COMPANIES:

                                       Signed as a deed for and on behalf of
                                       TRANSWORLD HEALTHCARE (UK) LIMITED

                                       By:
                                           -------------------------------------
                                           Name:
                                           Title:


                                       By:
                                           -------------------------------------
                                           Name:
                                           Title:

                                      S-1

<PAGE>

                    AMENDMENT NO. 1 TO VOTING TRUST AGREEMENT
                            UK PARENT SIGNATURE PAGE

         IN WITNESS WHEREOF, the parties have executed this Amendment No. 1 to
Voting Trust Agreement as a deed as of the date first above written.

                                       Signed as a deed for and on behalf of
                                       ALLIED HEALTHCARE GROUP LIMITED
                                       (formerly: TRANSWORLD HOLDINGS (UK)
                                       LIMITED) acting by its duly authorized
                                       attorney:

                                       By:
                                           -------------------------------------
                                           Name:
                                           Title:



                                       By:
                                           -------------------------------------
                                           Name:
                                           Title:

                                      S-2
<PAGE>

                    AMENDMENT NO. 1 TO VOTING TRUST AGREEMENT
                             TRUSTEE' SIGNATURE PAGE

         IN WITNESS WHEREOF, the parties have executed this Amendment No. 1 to
Voting Trust Agreement as a deed as of the date first above written.

                                       RICHARD GREEN


                                       -----------------------------------------
                                       Name:


                                       Address:
                                               ---------------------------------
                                       Telephone:
                                                 -------------------------------


                                       In the presence of:

                                       Name:
                                            ------------------------------------
                                       Address:
                                               ---------------------------------
                                       Occupation:
                                                  ------------------------------

                                       S-3
<PAGE>

                    AMENDMENT NO. 1 TO VOTING TRUST AGREEMENT
                             TRIUMPH SIGNATURE PAGE

         IN WITNESS WHEREOF, the parties have executed this Amendment No. 1 to
Voting Trust Agreement as a deed as of the date first above written.

                                       Signed as a deed for and on behalf of

                                       TRIUMPH PARTNERS III, L.P.

                                       By: Triumph III Advisors, L.P.,
                                              its general partner

                                       By: Triumph III Advisors, Inc.,
                                              its general partner

                                       By:
                                           -------------------------------------
                                           Name:
                                           Title:


                                       By:
                                           -------------------------------------
                                           Name:
                                           Title:

                                       Address:   Triumph Capital Group, Inc.
                                                  28 State Street, 37th Floor
                                                  Boston, MA 02109
                                                  Attn: Frederick S. Moseley, IV
                                       Telephone: (617) 557-6000

                                      S-4
<PAGE>

                    AMENDMENT NO. 1 TO VOTING TRUST AGREEMENT
                            US PARENT SIGNATURE PAGE

         IN WITNESS WHEREOF, the parties have executed this Amendment No. 1 to
Voting Trust Agreement as of the date first above written.

                                       Signed as a DEED by

                                       TRANSWORLD HEALTHCARE, INC.

                                       acting by its duly authorized attorney:


                                       By:
                                           -------------------------------------
                                           Name:
                                           Title:

                                       By:
                                           -------------------------------------
                                           Name:
                                           Title:

                                      S-5