The placards of the anti-war protesters in Parliament Square blamed him for all the world’s ills, from slaughter in Iraq to the death of a baby in Africa every three minutes.

But President Bush found a gallant rescuer in Gordon Brown, who offered him emergency legacy counselling with some of Britain’s top historians.

Among guests joining the Prime Minister for roast beef and trifle were Simon Schama, who has written on slavery, Martin Gilbert, an expert on the Holocaust, and David Cannadine, who wrote on the decline of the aristocracy. They were among 30 guests who attended the “semi-private” dinner with Mr Bush and his wife.

“He’ll be meeting with a group of historians,” Stephen Hadley, the President’s National Security Adviser, told journalists on the plane from Paris. “Ought to be an interesting evening.”

After leaving office, President Bush intends to write a book and is rumoured to be searching for ghost writers to help. It is expected to promote his freedom agenda and explain why he took America to war in Iraq.

One potential candidate spoken of is Andrew Roberts, who has written much about war leaders including Hitler, Churchill, Napoleon and Wellington and has already dined with the President at the White House.

Mr Roberts is understood to be among those who attended the Downing Street dinner. Another is Niall Ferguson, who has written extensively about empires, though he was not at Downing Street last night.

The President’s breathless week-long tour of five European capitals – six including the Vatican – has provided him with a chance to think about his legacy.

“Well, first of all, just so you know, I’m not going to be around to see it. There’s no such thing as objective short-term history,” he said. “It takes a while for history to have its, you know, to be able to have enough time to look back to see why decisions were made and what their consequences were.”

Mr Bush arrived at the Heathrow Royal Suite on the final leg of his “let’s do Europe tour” at 1.55pm yesterday. He was taken by helicopter to Windsor Castle for tea with the Queen. One part of the runway on the south side of the West London airport was barred temporarily to other traffic but a spokesman for BAA said that disruption would be kept to a minimum.

The President arrived at Downing Street at about 7pm for the dinner, which was largely organised by Sarah Brown. It was also attended by David Miliband, the Foreign Secretary, Alistair Darling, the Chancellor, Sir Nigel Sheinwald, the British Ambassador to Washington, and Stephen Carter, Mr Brown’s chief strategist.

As they ate, more than 2,000 protesters gathered in Parliament Square clashed with riot police. Several injuries were reported among the demonstrators.

Mr Bush later retired to the residence of the US Ambassador, Winfield House, in Regent’s Park, where he met some of the British troops serving alongside the Americans in Iraq. This morning Mr Bush will spend 90 minutes with Mr Brown in Downing Street, half of that time in private, before they are joined by officials. This afternoon the President and Prime Minister will fly to Belfast. Officials emphasised that Mr Bush had taken a close interest in Northern Ireland, particularly since the peace process has been taken “to the brink” after Sinn Fein declared that it would not work with Peter Robinson, successor to the Rev Ian Paisley as leader of the Democratic Unionist Party.

Aides have played down hyperbolic rumours that Mr Bush will follow Mr Blair and become a Roman Catholic.

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