Exhibit 99.1

BP p.l.c.

Unaudited pro forma consolidated income statement

The unaudited pro forma consolidated income statement for the three months ended 31 March 2013, presented herein, is presented to give effect to the sale of BP’s 50% shareholding in TNK-BP, and BP’s acquisition of an additional 18.5% shareholding in Rosneft (the “Transaction”). On 5 February 2013, BP filed a Report on Form 6-K with the US Securities and Exchange Commission (the “SEC”) which included an unaudited pro forma consolidated balance sheet as at 31 December 2012 and an unaudited pro forma consolidated income statement for the year ended 31 December 2012 giving effect to the Transaction.

Disposal of TNK-BP

In the BP Annual Report and Form 20-F 2012 the Transaction was disclosed as consisting of three tranches under which BP would receive $25.4 billion (including a $0.7 billion dividend received from TNK-BP in December 2012) and Rosneft shares representing a 3.04% stake in Rosneft; BP would then use $4.8 billion of the cash to acquire a further 5.66% in Rosneft from Rosneftegaz and $8.3 billion to acquire a further 9.80% stake in Rosneft from a Rosneft subsidiary. As disclosed in BP’s First quarter Form 6-K as filed with the SEC on a Report on Form 6-K dated 30 April 2013 (the “First Quarter Form 6-K”), on completion, the transactions between BP, Rosneft and the Rosneft subsidiary were instead settled on a net basis, such that BP received the 9.80% stake in Rosneft directly rather than receiving and immediately paying $8.3 billion in cash. The net result was the same.

The gain on disposal of BP’s investment in TNK-BP, recognized in the TNK-BP segment, was $12.5 billion:

	$ billion
Agreed cash disposal proceeds		25.4
Amount settled net in Rosneft shares (9.80% stake)		(8.3	)
TNK-BP dividend received by BP in December 2012		(0.7	)
Interest on cash proceeds		0.3
Disposal proceeds received in cash in the quarter		16.7
Shares in Rosneft received (9.80% and 3.04% stake)		10.8
Consideration received		27.5
Less: carrying value of investment in TNK-BP		(12.5	)
		15.0
Deferral of gain		(3.0	)
Gain on existing 1.25% investment in Rosneft		0.5
Gain on disposal of investment in TNK-BP		12.5

Disposal proceeds of $4.9 billion were used to purchase a 5.66% stake in Rosneft from Rosneftegaz ($4.8 billion described above plus $0.1 billion of interest). The net cash inflow relating to the transaction included in Net cash flow from investing activities in the cash flow statement was $11.8 billion.

Part of the gain arising on the disposal, amounting to $3.0 billion, has been deferred due to BP selling its investment in TNK-BP to Rosneft, which following the Transaction is now accounted for by BP as an associate. The deferred gain will be released to BP’s income statement over time as the TNK-BP assets are depreciated or amortized.

Investment in Rosneft

BP’s investment in Rosneft is included in the balance sheet as at 31 March 2013 filed with the First Quarter Form 6-K in the line Investments in associates. The investment is measured at cost less the deferred gain described above (in Roubles), plus post-acquisition changes in BP’s share of Rosneft’s net assets, and amounted to $13.0 billion at 31 March 2013:

	$ billion
Shares in Rosneft received		10.8
Shares purchased from Rosneftegaz		4.9
Value of agreements to purchase Rosneft shares accounted for as derivatives		(0.7	)
Deferred gain		(3.0	)
Amount included in capital expenditure		11.9
Value of existing 1.25% investment in Rosneft		1.0
Investment in Rosneft on completion		12.9
BP’s share of Rosneft’s post-acquisition earnings after tax		0.1
Investment in Rosneft at 31 March 2013		13.0

BP p.l.c.

Unaudited pro forma consolidated income statement

As disclosed in the First Quarter Form 6-K, the total amounts that will ultimately be paid by BP in relation to all the obligations relating to the Gulf of Mexico oil spill incident are subject to significant uncertainty and the ultimate exposure and cost to BP will be dependent on many factors, including in relation to any new information or new developments. These could have a material impact on our consolidated financial position, results of operations and cash flows. Except for those matters disclosed in BP’s Annual Report and Form 20-F 2012 and BP’s First Quarter Form 6-K, as at the date hereof, the management of BP is not aware of any matters that could materially impact the results and financial position as presented in the unaudited pro forma consolidated income statement. The unaudited pro forma consolidated income statement has been prepared on the following basis:

• The unaudited pro forma consolidated income statement has been prepared on the basis of the best information available to BP’s management and on the basis of assumptions that BP’s management believes are factually supportable and recurring.

• The unaudited pro forma consolidated income statement has been derived from BP’s unaudited consolidated financial statements for the three months ended 31 March 2013, Rosneft’s unaudited consolidated net income for the three months ended 31 March 2013 (as reported by Rosneft on 30 April 2013), and an estimate of the TNK-BP’s results for the three months ended 31 March 2013, derived from Rosneft’s Interim Condensed Consolidated Financial Statements (Unaudited) for the three months ended 31 March 2013.

• The unaudited pro forma consolidated income statement is presented to show the effect of the Transaction as if the Transaction had occurred on 1 January 2012.

• The unaudited pro forma consolidated income statement discloses income from continuing operations before non-recurring charges or credits directly attributable to the Transaction.

• The unaudited pro forma consolidated income statement should be read in conjunction with BP’s historical financial statements and accompanying notes.

• The unaudited pro forma consolidated income statement has been prepared for illustrative and informational purposes only and does not include adjustments for certain items, including those described below. As such, it is not intended to reflect what BP’s financial position and results of operations would have been had the Transaction occurred on the date indicated and is not necessarily indicative of our future financial position and future results of operations.

The pro forma adjustments represented in the unaudited pro forma consolidated income statement reflect the recognition of BP’s additional ownership of 18.5% of Rosneft, bringing BP’s total shareholding in Rosneft to 19.75%, with effect from 1 January 2012. The unaudited pro forma consolidated income statement includes adjustments to give effect to the following items:

• Removal of the $12,500 million gain on disposal of BP’s investment in TNK-BP.

• Adjustment for BP’s pro forma share of Rosneft’s profit after tax, adjusted to reflect pro forma net income to Rosneft of BP’s previous 50% share of TNK-BP as if the Transaction completed on 1 January 2012.

The unaudited pro forma consolidated income statement does not include adjustments for:

• The pro forma effect of Rosneft’s acquisition of AAR’s 50% stake in TNK-BP which was completed on 21 March 2013, except for actual results from the date of the acquisition.

• Fair values of BP’s share of Rosneft’s assets and liabilities acquired and associated goodwill, as required by International Accounting Standard (IAS) 28.

• Fair values of Rosneft’s share of TNK-BP’s assets and liabilities acquired and associated goodwill, as required by International Accounting Standard (IAS) 28.

• Income statement impacts, such as interest income, or interest expense saved, as a consequence of BP receiving net cash of $11.8 billion as a result of the Transaction.

• Any impact on earnings per share arising from BP’s statement that it will seek to offset any dilution of BP’s earnings per share arising from the Transaction.

• The impact of any fair value adjustments to Rosneft’s share of TNK-BP’s assets and liabilities, on Rosneft’s reported results.

BP p.l.c.

Unaudited pro forma consolidated income statement

BP p.l.c. unaudited pro forma consolidated income statement for the three months ended 31 March 2013

					Pro forma adjustments
	Notes		As reported		Gain on TNK-BP Disposal			Rosneft		As adjusted
$ million
Sales and other operating revenues				94,107		—			—		94,107
Earnings from joint ventures – after interest and tax				125		—			—		125
Earnings from associates – after interest and tax		1, 2		284		—			798		1,082
Interest and other income				157		—			—		157
Gains on sale of businesses and fixed assets		4		12,541		(12,500	)		—		41
Total revenues and other income				107,214		(12,500	)		798		95,512
Other components of profit before interest and taxation				87,076		—			—		87,076
Profit before interest and taxation				20,138		(12,500	)		798		8,436
Finance costs				282		—			—		282
Net finance expense relating to pensions and other post-retirement benefits				122		—			—		122
Profit before taxation				19,734		(12,500	)		798		8,032
Taxation		2		2,792		—			80		2,872
Profit for the period				16,942		(12,500	)		718		5,160
Attributable to
BP shareholders				16,863		(12,500	)		718		5,081
Non-controlling interests				79		—			—		79
				16,942		(12,500	)		718		5,160
Earnings per share – cents
Profit for the period attributable to BP shareholders
Basic		3		88.07							26.54
Diluted		3		87.61							26.40

See accompanying notes to unaudited pro forma consolidated income statement

BP p.l.c.

Unaudited pro forma consolidated income statement

Notes to Unaudited pro forma consolidated income statement

Basis of preparation

The unaudited pro forma consolidated income statement of BP has been derived from BP’s unaudited consolidated financial statements for the three months ended 31 March 2013, Rosneft’s Interim Condensed Consolidated Financial Statements (Unaudited) for the three months ended 31 March 2013 (as reported by Rosneft on 30 April 2013) and an estimate of the results of TNK-BP for the three months ended 31 March 2013, derived from Rosneft’s Interim Condensed Consolidated Financial Statements (Unaudited) for the three months ended 31 March 2013.

The unaudited pro forma consolidated income statement for the three months ended 31 March 2013 is presented to show the effect of the Transaction as if the Transaction had occurred on 1 January 2012.

The unaudited pro forma consolidated income statement discloses income from continuing operations, before non-recurring charges or credits directly attributable to the Transaction.

Pro forma adjustments and assumptions

The unaudited pro forma consolidated financial statements reflect the adjustments and assumptions set out in Notes 1 to 4 below.

Note 1 Pro forma adjustments relating to BP’s acquisition of an additional 18.5% stake in Rosneft

Under IFRS, BP accounts for its investment in Rosneft according to IAS 28, Investments in Associates. An investment in an associate is accounted for using the equity method from the date on which it becomes an associate. On acquisition of the investment any difference between the cost of the investment and the investor’s share of the net fair value of the associate’s identifiable assets and liabilities is accounted for as follows:

(a) goodwill relating to an associate is included in the carrying amount of the investment.

(b) any excess of the investor’s share of the net fair value of the associate’s identifiable assets and liabilities over the cost of the investment is included as income in the determination of the investor’s share of the associate’s profit or loss in the period in which the investment is acquired.

Appropriate adjustments to the investor’s share of the associate’s profits or losses after acquisition are also made to account, for example, for depreciation of the depreciable assets based on their fair values at the acquisition date or for the amortization of identified intangible assets which may or may not be recognized in Rosneft’s own financial statements. Similarly, appropriate adjustments to the investor’s share of the associate’s profits or losses after acquisition are made for impairment losses recognized by the associate, such as for goodwill or property, plant and equipment. BP is not yet able to finalize fair values and goodwill, therefore this unaudited pro forma consolidated income statement does not include any such adjustments.

Note 2 Pro forma information for Rosneft and TNK-BP

Financial information for Rosneft has been derived from its Interim Condensed Consolidated Financial Statements (Unaudited) for the three months ended 31 March 2013, prepared in Russian Roubles and under IFRS as published by the IASB. The following exchange rates have been used to convert Russian Roubles to US Dollars:

Income statement for the three months ended 31 March 2013 30.4019

BP’s share of Rosneft’s adjusted profit after tax is calculated as follows:

	Three months ended
	31 March 2013
Rosneft’s reported net income (billion Roubles )		101
TNK-BP result relating to BPs 50% share for 79 days		35
Rosneft’s adjusted net income (billion Roubles )		136
USD:RUB year-to-date average exchange rate		30.4019
Rosneft’s reported adjusted net income ($ million)		4,473
BP’s share (19.75%) of Rosneft’s adjusted consolidated net income ($ million)		883
Less: amount already recognized in BP’s
Unaudited Consolidated income statement		85
Net adjustment		798

BP p.l.c.

Unaudited pro forma consolidated income statement

Rosneft’s results above have been adjusted to reflect the net income of BP’s previous 50% stake in TNK-BP as if the Transaction completed on 1 January 2012.

Distributions from Rosneft to BP are subject to Russian withholding tax at a rate of up to 15%. In the unaudited pro forma consolidated income statement a provision has been recognized for this withholding tax at an assumed rate of 10% in accordance with the current UK/Russia Double Taxation Convention.

Note 3 Earnings per share

The weighted average numbers of BP ordinary shares outstanding during the years used to calculate earnings per share are as follows:

	Three months ended
	31 March 2013
Basic weighted average number of shares outstanding (thousand)		19,147,437
Weighted average number of shares outstanding used to calculate diluted earnings per share (thousand)		19,247,671

Note 4 Material nonrecurring credit which resulted directly from the Transaction

As a direct result of the Transaction, a gain on disposal of BP’s investment in TNK-BP in the amount of $12.5 billion was recognized in BP’s unaudited consolidated income statement for the three months ended 31 March 2013. The unaudited pro forma consolidated income statement has been adjusted to exclude this gain on disposal.