BP (BP)

OPINION OF COUNSEL TO THE COMPANY

Opinion of Sullivan & Cromwell LLP:

Ladies and Gentlemen:

In connection with the [several] purchases today by you pursuant to the Purchase Agreement, dated _______ (the “Purchase Agreement”), among BP Capital Markets p.l.c., a public limited company organized under the laws of England and Wales (the “Company”), BP p.l.c., a public limited company organized under the laws of England and Wales (“BP”), and you, of $______ principal amount of the Company’s ____% Guaranteed Notes due _____ (the “Securities”) issued pursuant to the Indenture, dated as of ______ (the “Base Indenture”), among the Company, BP and The Bank of New York Mellon Trust Company, N.A. (as successor to JPMorgan Chase Bank), as Trustee (the “Trustee”), as supplemented by the _____ Supplemental Indenture, dated as of ______ (the “______ Supplemental Indenture” and, together with the Base Indenture, the “Indenture”), we, as United States counsel for the Company and BP, have examined such corporate records, certificates and other documents, and such questions of law, as we have considered necessary or appropriate for the purposes of this opinion. Upon the basis of such examination, it is our opinion that:

(1) Assuming that the Indenture has been duly authorized, executed and delivered by the Company and BP, the Indenture constitutes a valid and legally binding obligation of the Company and BP enforceable in accordance with its terms, subject to bankruptcy, insolvency, fraudulent transfer, reorganization, moratorium and similar laws of general applicability relating to or affecting creditors’ rights and to general equity principles; and the Indenture has been duly qualified under the Trust Indenture Act of 1939.

(2) Assuming that the Securities have been duly authorized, the Securities will, when executed and authenticated in accordance with the terms of the Indenture and delivered to and paid for by you pursuant to the Purchase Agreement, constitute valid and legally binding obligations of the Company entitled to the benefits of the Indenture and enforceable in accordance with their terms, subject to bankruptcy, insolvency, fraudulent transfer, reorganization, moratorium and similar laws of general applicability relating to or affecting creditors’ rights and to general equity principles.

(3) Assuming that the guarantees of BP endorsed on the Securities (the “Guarantees”) have been duly authorized, executed and delivered by BP, upon due execution, authentication and delivery of the Securities, the Guarantees will constitute valid and legally binding obligations of BP enforceable in accordance with their terms, subject to bankruptcy, insolvency, fraudulent transfer, reorganization, moratorium and similar laws of general applicability relating to or affecting creditors’ rights and to general equity principles.

(4) The execution and delivery of the Purchase Agreement by the Company and BP, the execution and delivery of the Indenture by the Company and BP and the issuance of the Securities in accordance with the Indenture and the execution of the Guarantees by BP and the sale of the Securities by the Company to you pursuant to the Purchase Agreement do not violate any Federal law of the United States or law of the State of New York; provided, however, that, for the purpose of this paragraph (4), we express no opinion with respect to Federal or state securities laws, other antifraud laws, fraudulent transfer laws, the Employment Retirement Income Security Act of 1974 and related laws, and laws that restrict transactions between United States persons and citizens or residents of certain foreign countries or specially designated nationals and organizations.

(5) All regulatory consents, authorizations, approvals and filings required to be obtained or made by the Company or BP under the Federal laws of the United States and the laws of the State of New York for the execution of the Indenture by the Company or BP, the issuance of the Securities in accordance with the Indenture and the execution of the Guarantees by BP and sale of the Securities by the Company to you pursuant to the Purchase Agreement have been obtained or made; provided, however, that for the purpose of this

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paragraph (5), we express no opinion with respect to state securities laws.

(6) The Company is not required to register as an “investment company” under the Investment Company Act of 1940, as amended.

The foregoing opinion is limited to the Federal laws of the United States and the laws of the State of New York, and we are expressing no opinion as to the effect of the laws of any other jurisdiction.

In rendering the foregoing opinion, we have relied as to certain matters upon information obtained from public officials, officers of the Company and BP and other sources believed by us to be responsible, and we have assumed that each of the Company and BP has been duly organized and is an existing corporation in good standing under the laws of England and Wales, that the Indenture has been duly authorized, executed and delivered by the Trustee, that the Securities and the Guarantees conform to the specimens thereof examined by us, that the Trustee’s certificates of authentication of the Securities have been manually signed by one of the Trustee’s authorized officers, and that the signatures on all documents examined by us are genuine, assumptions which we have not independently verified.

[Disclosure Letter]

Ladies and Gentlemen:

This is with reference to the registration under the Securities Act of 1933 (the “Act”) and offering of $____ principal amount of ___ Guaranteed Notes due ____ (, the “Securities”) of BP Capital Markets p.l.c., a public limited company organized under the laws of England and Wales (the “Company”), and the related guarantees thereof by BP p.l.c., a public limited company organized under the laws of England and Wales (“BP”). The Registration Statement relating to the Securities (File Nos. 333-[            ] and 333-[            ]) was filed on Form F-3 in accordance with procedures of the Securities and Exchange Commission (the “Commission”) permitting a delayed or continuous offering of securities pursuant thereto and, if appropriate, a post-effective amendment, document incorporated by reference therein or prospectus supplement that provides information relating to the terms of the securities and the manner of their distribution. The Securities have been offered by the Prospectus dated _____ (the “Basic Prospectus”), as supplemented by the Prospectus Supplement dated ______ (the “Prospectus Supplement”), which updates or supplements certain information contained in the Basic Prospectus. The Basic Prospectus as supplemented by the Prospectus Supplement does not necessarily contain a current description of the Company’s and BP’s business and affairs since, pursuant to Form F-3, it incorporates by reference certain documents filed with the Commission that contain information as of various dates.

As United States counsel to the Company, we reviewed the Registration Statement, the Basic Prospectus, a final term sheet, dated _______, 20__ (the “Pricing Term Sheet”) and filed pursuant to Rule 433 under the Act (such Pricing Term Sheet, taken together with the Basic Prospectus being referred to herein as the “Pricing Disclosure Package”), and the Prospectus Supplement and participated in discussions with your representatives and those of the Company and BP and their accountants. Between the date of the Prospectus Supplement and the time of delivery of this letter, we participated in further discussions with your representatives and those of the Company and BP and their accountants concerning certain matters relating to the Company and BP and reviewed certificates of certain officers of the Company and BP, an opinion addressed to you from BP’s Group General Counsel and a letter addressed to you from the Company’s and BP’s accountants. On the basis of the information that we gained in the course of the performance of the services referred to above, considered in the light of our understanding of the applicable law (including the requirements of Form F-3 and the character of the prospectus contemplated thereby) and the experience we have gained through our practice under the Act, we confirm to you that, in our opinion, the Registration Statement, as of the date of the Prospectus Supplement, and the Basic Prospectus, as supplemented by the Prospectus Supplement, as of the date of the Prospectus Supplement, appeared on their face to be appropriately responsive, in all material respects relevant to the offering of the Securities, to the requirements of the Act, the Trust Indenture Act of 1939, and the applicable

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rules and regulations of the Commission thereunder. Also, we confirm to you that the statements contained under the captions “Description of Debt Securities and Guarantees” and “Tax Considerations” in the Basic Prospectus and under the captions “Description of Notes”, “Underwriting” and “United States Taxation” in the Prospectus Supplement insofar as they relate to provisions of documents or United States Federal tax law therein described and insofar as they relate to the offering of the Securities, constitute a fair and accurate summary of such provisions in all material respects.

Further, nothing that came to our attention in the course of such review has caused us to believe that, insofar as relevant to the offering of the Securities,

(a) the Registration Statement, as of the date of the Prospectus Supplement, contained any untrue statement of a material fact or omitted to state any material fact required to be stated therein or necessary to make the statements therein not misleading, or

(b) the Pricing Disclosure Package, as of [__:00] [A/P].M. on ______, __, 200_ , contained any untrue statement of a material fact or omitted to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading, or

(c) the Basic Prospectus, as supplemented by the Prospectus Supplement, as of the date of the Prospectus Supplement, contained any untrue statement of a material fact or omitted to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading.

We also advise you that nothing that came to our attention in the course of the procedures described in the second sentence of the first preceding paragraph has caused us to believe that the Basic Prospectus, as supplemented by the Prospectus Supplement, as of the time of delivery of this letter, contained any untrue statement of a material fact or omitted to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading.

The limitations inherent in the independent verification of factual matters and the character of determinations involved in the registration process are such, however, that we do not assume any responsibility for the accuracy, completeness or fairness of the statements contained in the Registration Statement, the Basic Prospectus, the Pricing Disclosure Package or the Prospectus Supplement except to the extent specifically noted in the fourth sentence of the second preceding paragraph. Also, we do not express any opinion or belief as to the financial statements or other financial data derived from accounting records contained in the Registration Statement, the Basic Prospectus, the Pricing Disclosure Package or the Prospectus Supplement, as to the report of management’s assessment of the effectiveness of internal control over financial reporting or the auditor’s report as to the effectiveness of internal control over financial reporting, each as included in the Registration Statement, the Basic Prospectus, the Pricing Disclosure Package or the Prospectus Supplement, or as to the statement of the eligibility of the Trustee under the Indenture under which the Securities are being issued.

This letter is furnished by us, as United States counsel to the Company, to you, as Representative of the Purchasers, solely for the benefit of the Purchasers in their capacity as such, and may not be relied upon by any other person. This letter may not be quoted, referred to or furnished to any purchaser or prospective purchaser of the Securities and may not be used in furtherance of any offer or sale of the Securities.

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