Ambac Assurance UK Limited's Statement Regarding Expiration of Confidentiality Agreements With Certain Holders of Bonds Issued by Metronet Rail BCV & Metronet Rail SSL.

NEW YORK -- Ambac Assurance UK Limited ("AUK") announced the expiration, as of today, of confidentiality agreements between certain holders of bonds ("Participating Bondholders") issued by Metronet Rail BCV ("BCV") and Metronet Rail SSL ("SSL") and AUK and Financial Security Assurance (UK) Limited (the "Monolines").

As previously announced on February 13, 2008, funds paid by London Underground Ltd ("LUL") in respect of the put option price on bonds issued by BCV and SSL are being held in escrow and are available to meet debt service and other amounts due in accordance with the Bond Trust Deed, escrow agreements and other relevant documentation.

AUK insures PS193 million of the SSL indexed-linked bonds and PS350 million of the BCV fixed rate bonds. The SSL bonds are indexed every six months, which affects the gross and net amounts. The debt was issued under Public Private Partnership ("PPP") contracts to finance the operation, maintenance and the initial phase of asset upgrades for part of the London Underground.

Under the applicable PPP contracts, insured bondholders and other senior creditors including commercial banks and the European Investment Bank benefit from an "Underpinned Amount" providing credit support from LUL. With respect to the AUK-insured BCV and SSL bonds, the sum of PS617 million has been received from LUL under this credit support and has been segregated through deposit into two separate escrow accounts opened in the joint names of AUK and Deutsche Trustee Company Limited ("Deutsche") at Citibank, N.A., London Branch. Deutsche is the Bond Trustee under the Bond Trust Deed governing the BCV and SSL bonds.

Within the confidentiality arrangements, the Participating Bondholders and the Monolines discussed various options relating to the application of funds currently standing to the credit of the escrow accounts relating to the bonds (the "Escrow Amounts").

The documentation relating to the bonds does not clearly set out how the Escrow Amounts should be applied. Escrow Amounts are currently being used to pay scheduled interest and principal. The Monolines and the Participating Bondholders have been discussing other possible applications of the Escrow Amounts, including: (i) collateral management (purchase of a suitable investment portfolio); (ii) a tender offer; or (iii) acceleration of the Bonds at par.

These discussions have not yet reached a conclusion. The Monolines will continue to work towards a decision regarding the application of the Escrow Amounts.

The funds held in escrow are available to meet debt service guaranteed by AUK and other amounts due in accordance with the Bond Trust Deed, the escrow agreement and other relevant documentation. While in escrow, the funds will be invested in UK government securities, entities which invest solely in UK government securities, any short term instruments or deposits with a rating of A-1 or better by S&P and P-1 or better by Moody's, or other investments as agreed by AUK and the Bond Trustee.

As is typical for insured transactions that experience an event of default, AUK has the right to direct that the funds held in escrow be used either to continue to meet debt service as scheduled or to fund the acceleration and immediate payment of all principal and interest due in accordance with the documentation.

AUK's unconditional and irrevocable guaranty remains in full force and effect.

Forward-Looking Statements

This release contains statements about our future results that may constitute "forward-looking statements" within the meaning of the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. These statements are based on management's current expectations and are subject to uncertainty and changes in circumstances. Actual results may differ materially from those included in these statements due to a variety of factors. More information about these factors is contained in Ambac Financial Group Inc.'s (ultimate parent company to AUK) ("Ambac") filings with the Securities and Exchange Commission. There are a variety of factors, many of which are beyond Ambac's control, which affect the operations, performance, business strategy and results and could cause its actual results to differ materially from the expectations and objectives expressed in any forward-looking statements. Readers are cautioned not to place undue reliance on forward-looking statements which speak only as of the date they are made. Ambac does not undertake to update forward-looking statements to reflect the impact of circumstances or events that arise after the date the forward-looking statements are made. The reader should, however, consult any further disclosures Ambac may make in its future filings of its reports on Form 10-K, Form 10-Q and Form 8-K.

Ambac Financial Group, Inc., headquartered in New York City, is a holding company whose affiliates provide financial guarantees and financial services to clients in both the public and private sectors around the world. Ambac's principal operating subsidiary, Ambac Assurance Corporation, a guarantor of public finance and structured finance obligations, has earned triple-A ratings from Moody's Investors Service, Inc. and Standard & Poor's Ratings Services; and a double-A rating from Fitch, Inc. Moody's, Standard & Poor's and Fitch all maintain a "negative outlook." Ambac Financial Group, Inc. common stock is listed on the New York Stock Exchange (ticker symbol ABK).