It used to be said that “when America sneezes, the rest of the world catches a cold”. These days, at the slightest sign of a sniffle in the US political process, British MPs catch a plane.

Frontbenchers from all three parties are flying across the Atlantic over the next fortnight for the Democratic and Republican conventions, hoping to contract the contagion known in Europe as “Obamamania” - and, perhaps, find out if the Republicans have a cure.

A four-strong delegation from the Labour Party is expected next week in Denver, where meetings are being arranged to tap into the expertise of Barack Obama's campaign, particularly over its use of the internet to galvanise activists and raise unprecedented sums in small donations.

Among those coming are David Lammy, the Skills Minister. He has emerged as a “point man” between the Government and Mr Obama - his former Harvard classmate with whom he campaigned earlier this year in Wisconsin. Also expected to attend are Ed Miliband, the Cabinet Office Minister, who has a key role in planning the next general election campaign, Stuart Wood, a Downing Street foreign policy adviser, and Rachel Cowburn, Labour's international officer.

Tickets for the Democratic convention are so prized that James Purnell, the Work and Pensions Secretary, has been told there is no room for him, even though Douglas Alexander, the International Development Secretary, has pulled out. Matthew Doyle, a senior aide to Tony Blair, is organising his own trip to the convention.

The Tories will be represented in Denver by Francis Maude, the Shadow Cabinet Office Minister, as well as Simon Burns, an opposition whip who - unusually for a Tory - has always identified with the Democrats.

The party is also sending a strong team to the Republican convention in St Paul the next week. This will be led by Liam Fox, the Shadow Defence Secretary, who was able to retain good relations with the Bush Administration during a five-year frost caused by Tory criticism of the war in Iraq.

The frontbenchers David Liddington, Mark Francois, Eleanor Laing and Brooks Newmark will join him at the convention to watch John McCain being anointed as the nominee. Steve Hilton, David Cameron's senior adviser who moved to California recently, is expected to show up at some point.One Labour strategist suggested yesterday that the party was making a mistake by not going to the Republican convention, saying: “McCain is fighting back hard against Obama, who has been slickly branded. Gordon [Brown] could do with a bit of what the Republicans are drinking.”

Mr Maude said: “I'm a strong supporter of McCain. But I think this is shaping up to be a very even race and we need to be in good shape with whoever wins the presidency. There is certainly a lot to be learnt from Obama - he's an interesting guy.”

Labour and the Tories have sought to associate themselves with the Democratic nominee, who is enormously popular in Britain. Mr Cameron projects himself as another youthful, charismatic politician promising change and even borrowed Mr Obama's slogan of “Yes, we can!” for a speech at the party's fundraising Black & White Ball.

But Labour is confident that Mr Obama, as the nominee of its sister party, will sign up for the international club of progressive leaders organised by the New Policy Network, a British centre-left think-tank. Last year it held a conference in Washington attended by Mr Purnell and John Hutton, the Business Secretary, together with Karen Kornbluh, Mr Obama's policy adviser.

Mr Brown has already ordered aides to examine the success that Mr Obama has had in raising more than $400 million (£210 million), much of it online in small sums from more than two million people. As leader of a party that is struggling to cope with multimillion-pound debts, the Prime Minister told The Times on a recent trip to Washington that he had been impressed by how Democrats had “managed to extend their reach to new groups of supporters and donors”.

But he added that “the political systems are not the same and there are legal constraints about asking for money in unsolicited e-mails”. Indeed, a senior Labour figure has warned his colleagues “not to get too starry-eyed about the Democrats”, saying: “Every four years we see people coming back from the convention like they are kids who've been to Disneyland.”

The Liberal Democrats are sending two former party leaders to Denver, Sir Menzies Campbell and Lord Steel of Aikwood - who has been to every Democratic convention since 1980 - along with Ed Davey, the party's foreign affairs spokesman and campaign chief. None is going to St Paul.

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