UK oil companies lobbied the government in the run-up to the war in Iraq and raised concerns that the US was pledging oil contracts to Russian companies in an attempt to overcome Moscow’s opposition to the invasion.

Documents released as part of the showed that representatives of oil groups such as , and met Baroness Symons, then UK trade minister, in October 2002 — five months before US-led forces entered Iraq — to discuss their potential role in postwar reconstruction.

“These discussions have taken place amid concerns that talks are being held between US officials and companies involved in these sectors from the US and other countries, eg Russia, without any involvement of the UK,” said a civil service briefing note for Sir David Manning, who was then foreign policy adviser to prime minister Tony Blair.

Separate documents cited reports by British officials of a meeting between Dick Cheney, US vice-president, and Yevgeny Primakov, a former Russian prime minister, in which Mr Cheney said: “Bids [for contracts] of those countries which co-operated with the US over Iraq would be looked at more sympathetically than those which did not.”

In her meeting with UK energy companies, Baroness Symons said she “could not make any definitive undertakings, given our determination that any action in relation to Iraq is prompted by our concerns over WMD, and not a desire for commercial gains”.

However, she subsequently told , foreign secretary in Tony Blair’s government, that she had promised to “draw this issue to your attention as a matter of urgency” and that UK companies “were genuinely convinced that deals were being struck and that British interests are being left to one side”.

Numerous similar exchanges are detailed in the Chilcot report laying bare the desire of UK companies for a share of the spoils from the opening of Iraq’s oil and gasfields once Saddam Hussein’s regime was overthrown. Documents show UK ministers and officials were desperate to avoid oil interests being seeing as a motivation for the war but also wary of losing out in the expected scramble for energy contracts.

Responding to a government paper that described securing contracts for British companies as a “second order objective”, Sir Christopher Meyer, then the UK’s ambassador to Washington, argued that this should in fact be a “top priority” in the UK’s planning for postwar Iraq and that “Mr Blair would have to pursue the issue with President [George W.] Bush if the UK were to have any impact”.

In the months and years after the invasion, the mounting frustration becomes clear of UK companies, ministers and officials over a perceived lack of British influence over Iraqi oil policy and over the dominance of US energy groups in the country.

In a letter to Mr Blair in June 2003, Mr Straw asked the prime minister to press the case for British companies “very forcefully” with Mr Bush. “As you know, the US are completely ruthless on favouring US companies, and will not help UK companies unless you play hardball with Bush”.”

Mr Blair subsequently raised concerns with the US president over the stalling of a bid by the UK arm of Siemens, the German group, for an electricity equipment contract in the face of competition from General Electric of the US. A few weeks later, British embassy officials in Washington reported a “favourable change” in attitudes towards the Siemens bid by the US-led coalition authority in Iraq.

Shell and BP declined to comment. BG Group is now part of Shell.