Exhibit 5.1


                   SIDLEY AUSTIN        BEIJING    GENEVA        SAN FRANCISCO
                   WOOLGATE EXCHANGE    BRUSSELS   HONG KONG     SHANGHAI
SIDLEY AUSTIN      25 BASINGHALL STREET CHICAGO    LONDON        SINGAPORE
- ----------------|  LONDON EC2V 5HA      DALLAS     LOS ANGELES   TOKYO
SIDLEY          |  DX NUMBER 580        FRANKFURT  NEW YORK      WASHINGTON, DC
                   LONDON CITY
                   +44 (0) 20 7360 3600
                   +44 (0) 20 7626 7937 FAX




Granite Master Issuer plc
Fifth Floor
100 Wood Street
London
EC2V 7EX



                                                              May 24, 2006



Dear Sirs


Granite Master Issuer plc (No. 5250668) Series 2006-2 Notes

1.       INTRODUCTION

1.1      We have acted as English legal advisers to Granite Master Issuer plc
         (the "Company") in connection with the issuance of U.S.$810,000,000
         Series 2006-2 Class A1 Notes due April 2031, (euro)300,000,000 Series
         2006-2 Class A2 Notes due April 2031, (pound)70,000,000 Series 2006-2
         Class A3 Notes due April 2031, U.S.$1,275,000,000 Series 2006-2 Class
         A4 Notes due December 2054, (euro)1,360,000,000 Series 2006-2 Class
         A5 Notes due December 2054, (pound)500,000,000 Series 2006-2 Class A6
         Notes due December 2054, U.S$29,000,000 Series-- 2006-2 Class B1
         Notes due December 2054, U.S. $36,000,000 Series 2006-2 Class B2
         Notes due December 2054, (euro)37,500,000 Series 2006-2 Class B3
         Notes due December 2054, U.S.$25,000,000 Series 2006-2 Class M1 Notes
         due December 2054, U.S.$25,000,000 Series 2006-2 Class M2 Notes due
         December 2054, (euro)35,000,000 Series 2006-2 Class M3 Notes due
         December 2054, (pound)10,000,000 Series 2006-2 Class M4 Notes due
         December 2054, U.S.$75,000,000 Series 2006-2 Class C1 Notes due
         December 2054, (euro)55,000,000 Series 2006-2 Class C2 Notes due
         December 2054 and (pound)12,000,000 Series 2006-2 Class C3 Notes due
         December 2054 (the "Series 2006-2 Notes") by the Company.

1.2      Unless otherwise defined, capitalised terms defined in the Issue
         Documents (as defined below) have the same meanings when used in this
         letter.

1.3      We have examined copies of the documents mentioned in the Schedule
         hereto and such other documents as we have considered necessary.

1.4      We have not made any investigation of, and do not express any opinion
         on, the law of any jurisdiction other than England and Wales.



        A list of partners' names and their professional qualifications
           is open for inspection at Woolgate Exchange 25 Basinghall
        Street, London, EC2V 5HA. All partners are either solicitors or
                          registered foreign lawyers.

    The offices listed above (other than London) are offices of associated
                         Sidley Austin Partnerships.

                         Regulated by the Law Society.




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1.5      The headings to paragraphs in this letter are for information purposes
         only and shall not otherwise form part of this letter.

2.       ASSUMPTIONS

2.1      In considering the documents referred to above and in rendering this
         opinion we have, without any further enquiry, assumed (save as
         expressly stated):

         (a)   the capacity, power and authority of each of the parties
               (other than the Company) to execute, deliver and perform the
               terms of the documents specified in Part I of Schedule
               (together, the "Issue Documents");

         (b)   the due execution and delivery of the Issue Documents;

         (c)   the conformity to original documents of any copy documents
               examined by us and that the copy of the Memorandum and
               Articles of Association of the Company examined by us is
               complete and up to date and would, if issued today, comply,
               as respects the Articles of Association, with Section 380 of
               the Companies Act 1985;

         (d)   that the Series 2006-2 Notes have been duly executed, issued
               and authenticated in accordance with the provisions of the
               Amended and Restated Issuer Trust Deed, the Issuer Paying
               Agent and Agent Bank Agreement and the Sixth Supplemental
               Trust Deed (each as defined in the Schedule);

         (e)   that no law of any jurisdiction outside England and Wales
               would render execution, delivery or issue illegal or
               ineffective and that, insofar as any obligation under any of
               the Issue Documents or the Series 2006-2 Notes is performed
               in, or is otherwise subject to, any jurisdiction other than
               England and Wales, its performance will not be illegal or
               ineffective by virtue of the law of that jurisdiction;

         (f)   that the information disclosed by our searches made today of
               the records at the office of the Registrar of Companies in
               London and at the Central Registry of Winding up petitions
               in relation to the Company was then complete, up to date and
               accurate and has not since then been materially altered or
               added to, and no notice of intention to appoint an
               administrator or an application for an administration order
               in respect of the Company has been presented or filed in any
               court in England and Wales;

         (g)   that the Company is not, on the date hereof, unable to pay
               its debts within the meaning of section 123 of the
               Insolvency Act 1986 (as amended) and will not


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               become unable to do so in consequence of the transactions
               effected by the Issue Documents;

         (h)   that the Minutes referred to in Part II of the Schedule
               represent a true record of the proceedings described therein of
               duly convened, constituted and quorate meetings of the Boards
               of Directors of the Company acting in the interests and for a
               proper purpose of the Company and that the relevant meetings
               will be duly held and that the authorisations to be given
               thereat will not subsequently been revoked or amended;

         (i)   that any factual matters referred to in each Issue Document
               will be true and accurate (including, without limitation, the
               accuracy of the representations and warranties therein);

         (j)   that the relevant Issue Documents have, in all material
               respects relevant hereto, been executed and delivered
               substantially in the form of the relevant exhibit to the
               Registration Statement;

         (k)   that none of the parties to the Issue Documents has taken or
               will take any action in relation to the Series 2006-2 Notes (i)
               which would be a contravention of Section 19 of the Financial
               Services and Markets Act 2000 (the "FSMA") or (ii) in
               consequence of anything said or done by a person in the course
               of carrying on investment business (within the meaning of the
               FSMA) in contravention of that Section;

         (l)   that (i) none of the Issue Documents will be entered into and
               none of the Series 2006-2 Notes will be issued in consequence
               of a communication in relation to which there has been or will
               be a contravention of Section 21 of the FSMA and (ii) no person
               has communicated or will communicate any inducement or
               invitation to engage in investment activity (within the meaning
               of the FSMA) in connection with the Issue Documents or the
               issue of the Series 2006-2 Notes in contravention of Section 21
               of the FSMA; and

         (m)   that any party to any of the Issue Documents which is subject
               to the supervision of any regulatory authority in the United
               Kingdom has complied and will comply with the requirements of
               such regulatory authority in connection with the issue,
               offering or sale of the Series 2006-2 Notes.

         We express no opinion as to matters of fact.


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3.       OPINION

         Based on the foregoing and subject to such legal and other
         considerations and qualifications as are stated herein, we are of the
         opinion that the Series 2006-2 Notes will constitute valid and
         legally binding obligations of the Company. As a result, those
         obligations would be enforceable in proceedings before the English
         courts.

4.       QUALIFICATIONS

         The opinions given in paragraph 3 of this letter are subject to the
         following qualifications:

         (a)   We do not express any opinion on European Community law as it
               affects any jurisdiction other than England and Wales.

         (b)   Any enforcement of the obligations of the Company in
               proceedings before the English courts would be by way of grant
               of a remedy in the event of a breach of those obligations. The
               nature and availability of the remedies provided by the English
               courts would depend on the circumstances. These remedies,
               including an order by the court requiring the payment of
               damages or the payment of a sum due, would be available subject
               to the principles of law, equity and procedures of general
               application. Some remedies, including an order by the court
               requiring specific performance of an obligation or the issue of
               an injunction, would be entirely within the discretion of the
               court. The possibility of obtaining any remedy would be lost if
               proceedings were not to be commenced within certain time
               limits. The English courts have power to stay proceedings and
               may decline jurisdiction, notably if concurrent proceedings are
               brought elsewhere. Accordingly, enforcement of the obligations
               of the Company under the Series 2006-2 Notes would not be
               certain in every circumstance.

         (c)   The obligations of the Company under the Series 2006-2 Notes
               will be subject to any law from time to time in force relating
               to liquidation or administration or any other law or legal
               procedure affecting generally the enforcement of creditors'
               rights.

5.       GENERAL

         We hereby consent to the filing of this opinion as an exhibit to the
Company's Report on Form 8-K dated the date hereof.


Yours faithfully,


/s/ Sidley Austin


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                                   SCHEDULE

                                    PART I

1.       The issuer trust deed dated 19 January 2005 between the Company and
         The Bank of New York, exhibited as Exhibit 4.6.1 to the Registration
         Statement (the "Issuer Trust Deed").

2.       The sixth supplemental issuer trust deed between the Company and The
         Bank of New York dated 24 May 2006 relating to the issue of the Series
         2006-2 Notes (the "Supplemental Issuer Trust Deed").

3.       The issuer paying agent and agent bank agreement amended and restated
         on 25 January 2006 between, inter alios, the Company and Citibank,
         N.A., exhibited as Exhibit 4.7 to the Registration Statement (the
         "Amended and Restated Issuer Paying Agent and Agent Bank Agreement").

4.       The form of Global Note Certificate for each Class of Series 2006-2
         Notes.



                                    PART II

The Minutes of a Meeting of the Board of Directors of the Company held on 17
May 2006.




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