Leading article: Europe's new dynamic holds risks for Britain

As Europe prepared for François Hollande's likely victory in France, two considerations were consistently uppermost.

The first was that an Hollande presidency could severely strain the Franco-German partnership. The second was that, whatever the outcome, British-French relations would remain on an even keel. When Mr Hollande follows his recent predecessors in making his first foreign trip as President-designate to Germany, the first preconception could be confounded. The second could follow in short order – and not in a good way.

The notion that Mr Hollande and Angela Merkel would start out on the wrong foot reflected the belief that a centre-left French President and a centre-right Chancellor would find it harder to get along than two leaders of similar ideological persuasion. Mr Hollande's promises to favour growth above austerity also seemed to bode ill for a co-operative approach, given Ms Merkel's devotion to debt reduction and sound housekeeping. When Mr Hollande said in his victory speech, "Austerity no longer has to be our destiny", it was not hard to imagine alarm bells ringing in Frankfurt and Berlin.

Yet every French leader, as every German leader, is familiar with the imperative that drives them together, especially at this time of uncertainty for the euro. Nor have divergent party allegiances been any bar to productive working relations. Nicolas Sarkozy and Ms Merkel were very different characters, even if they eventually became so close that Ms Merkel was ready to help campaign for Mr Sarkozy. On this, fortunately for Ms Merkel, wiser counsel prevailed.

Thus saved from herself, the German Chancellor can open relations with a clean slate. And the early signs are that, temperamentally, she may find it easier to deal with Mr Hollande – a less flamboyant and more consensus-oriented character, much, in fact, like herself. Even their divergence on the central question of growth and austerity could evolve into a difference of emphasis rather than principle. A new flourishing of Europe's Franco-German dynamo cannot be excluded.

Relations with London, on the other hand, could easily move in the opposite direction. While Ms Merkel sensibly decided against campaigning for Mr Sarkozy, the Prime Minister declined even to grant Mr Hollande a courtesy call during his campaign trip to London. It is true that relations between Mr Cameron and Mr Sarkozy had their ups and down. The ups were defence cooperation and the joint air intervention in Libya, where it was possible to discern the kernel of a new European and transatlantic defence settlement. The downs were French arms sales to India, but most of all Mr Cameron's refusal to sign Britain up to the financial stability pact. The way Mr Sarkozy ignored Mr Cameron at the following EU summit seemed to consign Libyan co-operation to the distant past.

The cooling of relations with Mr Sarkozy, however, does not mean that the arrival of Mr Hollande will necessarily instil warmth between London and Paris. Mr Hollande is a French Socialist of traditional pro-Europe views; Mr Sarkozy saw himself as an Atlanticist and took France back into the Nato command structures. Will Mr Hollande spare defence when he wants to find money for his social programmes? If Britain and France can no longer see eye to eye here, and Mr Cameron remains aloof from the euro crisis, there will be less for Britain and France to talk about, let alone agree on.

And the loser here would not be France, which would be comfortably ensconced in the bosom of Europe, but Britain, once again out on a limb. This might suit Conservative Eurosceptics, but it would be extremely disadvantageous for Britain, especially when the country is in such desperate need of economic growth. Mr Cameron would do well to seek talks in Paris, and fast.