As Hillary Clinton and Barack Obama tear each other apart in their quest for the Democratic nomination, Mr McCain — with the luxury of having wrapped up the Republican nomination - will use the coming weeks to focus on national security and foreign policy, the centrepiece of his general election strategy.

After a visit to Exeter in New Hampshire, next Wednesday, to thank the Granite State for resurrecting his campaign there on January 8, Mr McCain will lead a congressional delegation to Europe and the Middle East.

The trip is officially Senate business, during the Easter break for Capitol Hill, but it is very much aimed at burnishing his foreign policy credentials ahead of the election in November.

He will return on Easter Sunday, March 23, and deliver a speech drawing on his observations of the trip as he begins to draw a sharp contrast against his Democratic rivals over Iraq and terrorism.

There had been discussion inside his campaign of a speech at the London School of Economics during his visit to the city but that is now unlikely to take place, his aides say.

When he returns Mr McCain will begin a tour of America, highlighting not only his military background and years as a prisoner of war in Vietnam, but his family history. His father and grandfather were admirals in the US Navy. He will also hold as many fundraisers as possible. He held two yesterday and will hold another three today.

The US tour will begin in Meridian, Mississippi, where his father's family came from. The airfield at the naval air station is named after his namesake and grandfather.

Aides to Mr McCain consider the intensifying battle between Mrs Clinton and Mr Obama as a boon. While it frequently keeps Mr McCain off the front page, it allows him to start making his case to the American people, framing the general election debate and marshalling the Republican machine and party behind him — in contrast to the Democratic party, which is in danger of being torn apart by the nomination fight of his rivals.

Mr McCain will also begin fleshing out policy proposals to tackle the faltering US economy, which has become the predominant concern of voters.

He spoke more about the economy than any other issue yesterday, after a report by the US Labour Department showed the biggest monthly job losses in five years in February.

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