British Prime Minister Gordon Brown and French President Nicolas Sarkozy have taken strides to burnish the image of cross-Channel relations.

At a one-day summit held at Arsenal football club's London stadium, they agreed to cooperate on civil nuclear technology, call for greater global financial transparency and to be the best of friends.

Brown said: "We agree that only by working together can we confront the challenges we face, from terrorism to climate change, poverty, disease and from failed states. We believe that, working together, France and Britain can be even a greater force for good in the world of tomorrow and so, if you like, this will be an 'entente formidable' as well."

Sarkozy has also sought to boost France to full standing in NATO and lead European co-operation in defence. He promised parliament he would send more troops to Afghanistan.

How long his love for Britain would last was questioned, given the recent strain with Germany.

He made this pledge: "I believe I can demonstrate that it is a firm alliance. And it is that much more so since it is not against anyone. I know perfectly well that a French president has an historic responsibility to continue a friendly partnership with the Germans, because it counts. But I have always said that that was not enough in a Europe of 27 member states, and that we needed the English."

The guest, whose public opinion ratings at home are in a trough, was also asked whether he was worried his new wife Carla Bruni would steal the limelight.

The president replied that he was "moved" by the warm reception she had received and proud of how well she had represented France.