By Daniel Dombey and Andrew Ward in Washington and Andrew Bounds in Brussels

Five years ago, the notion of spending even a week in western Europe would have been distinctly unappetising for President George W. Bush.

But on Monday Mr Bush set off, on what is likely to be his last extended presidential trip to the continent, with a spring in his step.

Changes of government in Europe, conciliatory efforts by Washington and the decline of Iraq as the defining issue of the transatlantic relationship have made ties both more workmanlike and more congenial since the days when relations touched a historic low.

“His willingness to go to Paris, London, Berlin and Rome during the same trip shows how far we have come over the past few years,” said Simon Serfaty from the Center for Strategic and International Studies, a Washington-based thinktank.

“To some extent, he has gotten both sides of the Atlantic back from where they were a while ago.”

Strikingly, speaking before departing for Europe, where he will begin his visit with a US-European Union summit in Slovenia, the president did not mention Iraq once. After the reduction of British forces, the US no longer expects any big commitment of troops to Iraq by its European allies.

Instead, Mr Bush emphasised Afghanistan, and said he would remind those European countries that have sent soldiers that “there’s a lot of work to be done”. Presidential aides have also highlighted Mr Bush’s desire for Europe to tighten sanctions on Iran.

With Washington’s focus firmly more on Iran and Afghanistan, relations with old Iraq-war allies – such as the UK, Poland and Spain – no longer feature so highly.

This shift has been assisted by changes among Europe’s leaders.

Mr Bush’s wartime allies, Tony Blair and José Maria Aznar, have been replaced by prime ministers Gordon Brown in the UK and José Luis Rodríguez Zapatero in Spain, both of whom have cooler relationships with the president.

Meanwhile, the two staunchest European opponents of the war – French president Jacques Chirac and German chancellor Gerhard Schröder – have been replaced by more pro-American leaders Nicolas Sarkozy and Angela Merkel. In addition, the president’s friend, Silvio Berlusconi, has returned as Italy’s prime minister, despite the domestic unpopularity of his support for Mr Bush in Iraq.

Diplomats add that transatlantic relations have also been facilitated by a diplomatic initiative authorised by Mr Bush at the beginning of his second term in 2005, in which the US increased co-operation with the EU on Iran as well as other big issues such as Afghanistan.

And while in recent years bilateral co-operation has been constrained by Mr Bush’s low popularity ratings in much of Europe, recent opinion polls suggest that European perceptions of the US may be rebounding – partly owing to the enthusiasm about the US presidential election campaign.

But the European diplomat cautioned that neither the decades-old US-UK “special relationship”, nor the more edgy relationship with France, had been wholly transformed.

“You will still find some of the usual differences,” he said, citing France’s disputes with the US over genetically modified food and US poultry imports, and the two countries’ diverging analyses of the Middle East.

Moreover, just as US officials believe that Europe could do more on Iran and Afghanistan – a demand likely to be stepped up whether John McCain or Barack Obama wins the presidency – it may be hard for Washington to meet Europe’s expectations on measures to combat climate change.

Both Mr Obama and Mr McCain support mandatory caps on carbon emission, but last week’s collapse of legislation to set up a US cap-and-trade system brought a reminder that congressional support for their proposals cannot be taken for granted.

In Europe’s capitals, diplomats insist they are trying to control expectations for a new era after January 2009. As one EU official puts it: “The best way not to be disillusioned is to avoid having illusions.”