But the Foreign Office says this is normal practice. On releasing the information, the Foreign Secretary, Margaret Beckett, said: 'Honorary awards to citizens where Her Majesty the Queen is not head of state are not formally announced.'

According to the Foreign Office list the Queen approved Bechtel's honour for 'services to UK-American commercial relations' on 25 April 2003 - just a week after the company won a bumper £430m contract to rebuild Iraq's infrastructure after the invasion.

The honour to one of America's wealthiest citizens, a man with intimate ties to the Republican administration, will reignite the row over the secretive honours process.

The list shows that under Straw the Foreign Office awarded honours to several senior US military personnel involved in the Iraq invasion. These included the US military commander General Tommy Franks, known as 'Mr Shock and Awe' for his role in devising the battle plan for the 2003 invasion.

Others include Vice-Admiral Timothy Keating, who was in charge of all maritime forces involved in Operation Iraqi Freedom; Rear Admiral Barry Costello, commander of the Third Fleet and Task Force 55 during the Iraq invasion; Lieutenant-Colonel Mark Childress; and General Tad Moseley, chief of staff to the US Air Force.

The row comes as protests mount at the CBE given to Andy Hayman, the head of Scotland Yard's anti-terror operations who is at the centre of investigations into the shooting of Jean Charles de Menezes at Stockwell tube station last July and the raid at Forest Gate, east London, earlier this month.

Bechtel, who has a personal fortune of more than $3bn (£1.62bn), is 50th on America's rich list. British ministers have awarded his company contracts for the London Underground, the upgrade of the west coast main line, the Channel Tunnel rail link and the Jubilee Line extension. Bechtel's nuclear subsidiary has received almost £30m to help set up the Nuclear Decommissioning Authority.

Bechtel's contracts for US reconstruction work in Iraq have caused the most controversy. One of the firm's key board members is George Schultz, who was secretary of state under Ronald Reagan and who, as chairman of the Committee to Liberate Iraq, was one of the loudest cheerleaders for regime change.

The full list of awards to non-British citizens was only disclosed after Beckett agreed to place the details in the House of Commons Library following a series of parliamentary questions by the Liberal Democrat MP Norman Baker.

Baker said: 'This shows that what matters in Tony Blair's Britain is those with power, money and a US accent. These awards are supposed to be for good works and those that have helped Britain. Instead it seems they are being handed out to those who have supported Blair's misguided policies at home and overseas.'

Earlier this year The Guardian disclosed that Hans Rausing, the Swedish billionaire and former head of Tetra Pak, was awarded an honorary knighthood for philanthropy in January despite questions over his use of legal loopholes to avoid paying tax.

A spokesman for the Foreign Office confirmed that Bechtel had been awarded a CBE but said he could not give any details about the nomination process.