David and Nicolas – the best of amis

Fiscal squabbles were forgotten as the Prime Minister and his French counterpart showed unity on defence policy and much else. John Lichfield reports in Paris

Anglo-French spats may come and go but the blood-brotherhood of right-of-centre politics lasts forever.

The Prime Minister, David Cameron, yesterday shrugged off the cross-Channel slanging-match of late last year and gave his enthusiastic support to French President Nicolas Sarkozy's campaign for re-election.

After a Franco-British summit in Paris, Mr Cameron went out of his way to laud the "energy and courage" of a French president who once described him as "behaving like a stubborn kid".

"I think that he has done great things for his country," Mr Cameron said, with Mr Sarkozy grinning alongside him. "I wish my friend well in the battle that lies ahead."

Opinion polls show that Mr Sarkozy, of the centre-right Union Pour un Mouvement populaire (UMP), is trailing the Socialist challenger, François Hollande, in the two-round election in April and May.

Mr Cameron made it clear, however, that unlike Chancellor Angela Merkel of Germany, he has no intention of joining in Mr Sarkozy's uphill battle to win a second term. A British prime minister appearing on the campaign trail in France "might not have the effect intended", Mr Cameron said.

Anglo-French relations are wonderful, the two leaders insisted yesterday, but not so wonderful that a Conservative British PM could hope successfully to harangue the French electorate.

The annual Franco-British summit had been postponed from last November when the two countries were squabbling over plans to tighten fiscal discipline in the EU. The leaders yesterday announced a series of cross-Channel agreements on defence and energy cooperation, including a £400 million deal with the French nuclear power company Areva, which will create 1,500 jobs in Britain (see below).

Mr Sarkozy and Mr Cameron also built on the ground-breaking defence co-operation treaty they negotiated in London in November 2010. They signed a letter of intent to develop a pilotless, radar-busting, fighter aircraft which could transform aerial combat from the 2020s.

They also agreed to accelerate plans to create a mobile Franco-British control and command centre which could run joint military operations like those over Libya last year. Significantly, both men said that the Franco-British defence partnership would focus in future on the nuclear aspects of defence policy. In the past, the two countries have rejected developments such as shared nuclear submarine patrols but they have agreed to share some aspects of nuclear testing and research.

"The defence co-operation is real, it is substantial, it is going to make a big difference to the military capabilities of both Britain and France," Mr Cameron said yesterday. By "combining" their military capacity the two countries hoped to do just as much, or more, for less, he said.

"And it also covers the most sensitive defence areas of all, including... the nuclear issue," Mr Cameron added. This implied that more elaborate forms of Anglo-French military-nuclear co-operation were again on the table.

The two leaders praised one another for their role in leading the western military intervention in Libya last year which helped to topple Muammar Gaddafi. Both spoke of the need to prevent further bloodshed in Syria.

President Sarkozy said it was a "scandal" that a "state could massacre its own people". Democracies, he said, should never submit to the "diktat of dictatorships". But the international community was powerless, he said, to "impose a revolution from the outside" while the Syrian opposition was divided.

As for the December spats over the EU fiscal treaty blocked by Mr Cameron, Mr Sarkozy said that the two governments were now looking for ways to "respect" each other's "red lines".

"We have had divergences of views but perhaps, had I been in David Cameron's position, I would have defended Britain's interests in exactly the same way," Mr Sarkozy said.