The second-biggest rally addressed by Barack Obama this year, aside from his victory speech in Chicago on 4 November, was on 24 July in Berlin, when the then Democratic candidate for president set out his vision before 200,000 people for a closer alliance between the US and Europe.

Two days later, at the conclusion of his Continental tour, after seeing first Tony Blair for breakfast and then Gordon Brown in Downing Street, Obama met David Cameron, the Conservative leader, in a sunny corner of New Palace Yard at the Houses of Parliament.

The initial part of the conversation was picked up by an American ABC News microphone: an inane exchange, instigated by Cameron, about the need to take regular breaks. "You should be on the beach," said the Tory, with Obama agreeing that "you've got to refresh yourself".

What is not publicly known is that there was less agreement when, soon afterwards, the discussion turned substantial in Cameron's Commons office. Obama began by saying that he hoped to work closely with the EU. But, in a crude attempt to demonstrate his Atlanticist credentials, Cameron went on to indulge in what one source has described as an "anti-European diatribe", repeatedly referring to the "anti-Americanism" of EU member states. Cameron apparently told Obama that he would not encounter a more pro-American politician than himself.

If Cameron thought this would impress Obama, he was wrong. It would appear he had failed to study the multilateralist candidate's Berlin speech 48 hours previously. Obama had condemned "voices that deride and deny the importance of Europe's role in our security and our future", and went on: "Yes, there have been differences between America and Europe . . . But the burdens of global citizenship continue to bind us together . . . In this new century, Americans and Europeans alike will be required to do more - not less. Partnership and co-operation among nations is not a choice; it is the one way, the only way, to protect our common security and advance our . . . humanity. That is why the greatest danger of all is to allow new walls to divide us from one another."

On meeting Cameron, Obama was, according to diplomatic sources, "distinctly unimpressed", contrary to some reports (excitedly spun by the Conservatives) which suggested that the two men had formed an instant "bond". Instead, I have been told, Obama exclaimed of Cameron after their meeting: "What a lightweight!" He apparently also asked officials about Tory Euroscepticism. Soon, word about the rather awkward encounter between the two self-professed candidates of change made its way quietly round the upper echelons of Whitehall.

A widely read, broad-minded internationalist, Obama has long valued Europe and, asked during the primaries against Hillary Clinton to name the crucial US allies, he instantly placed "the European Union" at the top of the list. Perhaps more importantly, on defining international issues such as the invasion of Iraq (unlike Clinton and certainly unlike Cameron), Obama's position was closer to that of mainstream Europe - which, as led by President Jacques Chirac of France, tended to be more "doveish" than "hawkish".

Indeed, it is one of many symptoms of the British media's love affair with Cameron that his support for the disastrous invasion of Iraq is now seldom mentioned. Cameron, who also talked of the need for "judgement" in his chat with Obama, was among those Tories backing the then-leader Iain Duncan Smith, despite opposition from a considerable faction within the party. This group was led by Kenneth Clarke, who correctly predicted that the Iraq misadventure would bring terror to Britain's streets.

Today, Cameron's closest aides are the shadow schools minister, Michael Gove, an ideological neoconservative, and George Osborne, who opposed David Davis's attempts to force the Tories to take a civil-libertarian approach in opposing the government's anti-terrorist measures. Both Hague and Osborne were present at the meeting with Obama, yet Cameron's, Hague's and Osborne's approaches to the issues of the day are diametrically opposed to those of the president-elect. This is why the Tory leader's attempts to cash in on Obama's message of "change" and to compare himself to the Democrat were always so absurd.

And although Obama has dismayed many supporters and threatened his own image as a progressive change-maker by appointing the previously pro-war Hillary Clinton as secretary of state, most of his team do not like what they know of British Conservatism. Susan Rice, the new US ambassador to the United Nations, entered politics partly in horror at Tory refusal to intervene in the Balkans or in the Rwandan genocide of 1994. Joe Biden, the incoming vice-president, has said that when he examined the Tory policy of appeasing Slobodan Milosevic in the 1990s he could hear "the tap, tap, tap of Chamberlain's umbrella at Munich".

Obama's incoming national security adviser, James Jones, led Nato and was the EU's favourite American general. At a time when the new team at the White House wants to build bridges with Europe, Cameron's fervent hostility to the EU will cause dismay.

As a senior Labour source said: "Obama will want to work with a united Europe, not the 27 divided nations envisaged by a David Cameron, William Hague and [the Eurosceptic backbencher] Bill Cash vision of Europe. Tory isolationism is the last thing Obama's new foreign policy team will want from London."

Cameron continues to preside over the most anti-European parliamentary party in Conservative history. He has threatened to withdraw from the right-wing European People's Party grouping, much to the embarrassment of some leading Tory MEPs. The disclosure that his ideological opposition to Europe has disappointed Obama is also likely to cause considerable embarrassment - and not just to the Conservative leader himself.