The United States and Britain have repeatedly called on Nato allies to boost their contributions to the force in Afghanistan, where they are battling a Taleban that seems to be growing in strength.

On a two-day state visit aimed at improving awkward ties, Mr Sarkozy and British Prime Minister Gordon Brown both vowed to boost cooperation on the international economy and immigration.

In a passionate speech, Mr Sarkozy sketched a vision of far-reaching economic and defence cooperation and said France would send more troops to fight the Taleban if Nato backed its proposals. Paris has not yet made public its plans or gone into detail about troop numbers.

'If these proposals are accepted, France will propose at the (forthcoming Nato) summit in Bucharest, reinforcing its military presence. We cannot accept the return of the Taleban and al Qaeda to Kabul,' he told lawmakers to applause.

Foreign Secretary David Miliband told Reuters after the speech: 'I think there's a very clear signal that France wants to fulfil all of its responsibilities, diplomatic and military, in Afghanistan and that's obviously extremely welcome.'

Mr Sarkozy said he would for ask Mr Brown's help in getting Washington to halt a plunge of the US dollar making European exports more expensive. Britain rejects the idea of managing foreign exchange levels, saying markets are the best guide.

Mr Brown, who will hold talks with Mr Sarkozy on Thursday, said a new era was dawning for the 'entente cordiale' - a treaty signed by the two countries in 1904 - in which Britain and France would speak as one on international economic reform.

The neighbours, though bound together by mainstream European institutions like the European Union and Nato, have a love-hate relationship and mutual suspicion goes back centuries. But in an increasingly global world their economies now overlap everywhere.

'Brotherhood'
'I have come to propose to the British people that together we write a new page in our common history, that of a new Franco-British brotherhood,' Mr Sarkozy told members of parliament.

The French president, accompanied by his new wife, former model Carla Bruni, was welcomed by Queen Elizabeth with a state carriage procession to Windsor Castle, near London.

Several British newspapers marked the visit by printing an old picture of Bruni posing nude. But fashion gurus hailed the elegance of the Dior outfits she donned for the occasion, likening her to Jackie Kennedy.

Queen Elizabeth, hosting a sumptuous state banquet in Windsor Castle, hailed what she called 'respectful yet competitive' Anglo-French relations.

'The Internet, the Eurostar and even the camera phone have helped transform the way our respective populations interact,' she said.

'What is different is to be celebrated, what is similar should be embraced ... We are doing so much more together.'

Mr Brown and Mr Sarkozy have struck up a good relationship since coming to power last year. But Mr Brown's popularity has waned and Mr Sarkozy's standing has sunk since he married Ms Bruni last month.

Political analysts say Mr Sarkozy is reaching out to Britain because of difficulties with German Chancellor Angela Merkel.

Berlin and Paris traditionally dominate the European Union. -- REUTERS