Exhibit 8.1 SIDLEY AUSTIN LLP |BEIJING GENEVA SAN FRANCISCO 787 SEVENTH AVENUE |BRUSSELS HONG KONG SHANGHAI SIDLEY AUSTIN LLP NEW YORK, NY 10019 |CHICAGO LONDON SINGAPORE - ----------------| 212 839 5300 |DALLAS LOS ANGELES TOKYO SIDLEY | 212 839 5599 FAX |FRANKFURT NEW YORK WASHINGTON, DC | | |FOUNDED 1866 September 19, 2006 Granite Master Issuer plc Fifth Floor 100 Wood Street London EC2V 7EX England Re: Granite Master Issuer plc Granite Finance Funding 2 Limited Granite Finance Trustees Limited Series 2006-3 Notes ------------------- Ladies and Gentlemen: We have acted as United States tax counsel for Northern Rock plc, a public limited company incorporated under the laws of England and Wales, in connection with the issuance of $1,000,000,000 Series 2006-3 callable class A1 notes due December 2030; $1,800,000,000 Series 2006-3 callable class A3 notes due December 2054; $1,000,000,000 Series 2006-3 callable class A4 notes due December 2054; $1,750,000,000 Series 2006-3 callable class A7 notes due December 2054; $70,000,000 Series 2006-3 callable class B1 notes due December 2054; $182,000,000 Series 2006-3 callable class B2 notes due December 2054; $90,000,000 Series 2006-3 callable class M1 notes due December 2054; $100,000,000 Series 2006-3 callable class M2 notes due December 2054 and $60,000,000 Series 2006-3 callable class C2 notes due December 2054 (the "Series 2006-3 US Notes") by Granite Master Issuer plc (the "Issuer"). The Series 2006-3 US Notes will be issued pursuant to the Seventh Supplemental Issuer Trust Deed dated September 19, 2006 to the Issuer Trust Deed dated January 19, 2005 between The Bank of New York and the Issuer. We have advised the Registrants with respect to certain United States federal income tax consequences of the issuance of the Series 2006-3 US Notes. This advice is described under the headings "Summary of prospectus supplement - - Material United States tax consequences" and "Material United States tax consequences" in the prospectus supplement relating to the Series 2006-3 US Notes (the "Prospectus Supplement"), and "Summary of prospectus - United States federal income tax" and "Material United States tax consequences" (collectively, the "Discussions") in the prospectus relating to the Series 2006-3 US Notes (the "Prospectus"), which Prospectus Supplement and Prospectus have been filed with the Securities and Exchange Sidley Austin LLP is a limited liability partnership practicing in affiliation with other Sidley Austin partnerships SIDLEY AUSTIN LLP - ----------------| SIDLEY | Page 2 Commission. We hereby confirm and adopt as our opinion the opinions set forth in the Discussions. This letter is based on the facts and circumstances set forth in the Prospectus Supplement and Prospectus and in the other documents reviewed by us. We hereby consent to the filing of this letter as an exhibit to the Issuer's Report on Form 8-K dated the date hereof. Very truly yours, /s/ Sidley Austin LLP