British newspapers on Saturday leapt on allegations that Francois Hollande is having an affair with an actress, splashing the story over the front pages and poking fun at the French president.

The story even made page one of the normally staid Financial Times as the British press described the claims as a "crisis" for Hollande, who is already struggling with unpopularity and economic woes.

Both The Times and the Financial Times ran editorials on the subject, in a measure of how big the story is across the English Channel.

Pictures of actress Julie Gayet dominated the front of at least three national newspapers, with the conservative Daily Telegraph showing her in a particularly low-cut, backless dress.

The Times ran with the headline 'Oui Mr President'. The actress, the scooter and an affair of state', referring to the report in Closer magazine which said that Hollande arrived at her flat on the back of a moped.

Its editorial strongly argued in favour of Closer magazine's publication of the allegation.

It said "the public interest is clear" both because of Hollande's position and also because of the security implications of his scooter travel.

Instead of suing Closer, it added, "he would be wiser to accept the indulgent verdict of the magazine's editor that 'he's a President who has a crush,' and get on with governing a country in dire need of decisive governance."

The Times also carried a spoof column pretending to be the president's diary for the week -- written in "Franglais", a mixture of French and English that is beloved of British satirists -- in which the fake Hollande says: "Je suis le sexy, dirty chien!" (I am a sexy, dirty dog).

It also features a joke cameo from German Chancellor Angela Merkel who tells him: "Du bist einen ludicrous slaphead."

The Financial Times, not normally given to running large colour pictures of actresses on its front page, featured a photo of Gayet in a sober black dress.

Its editorial was more charitable to Hollande than the Times's, saying that he should be allowed to "eat his croissants in peace" while he tackles France's problems -- and adding that he could not be called an adulterer because he had never been married.

The Telegraph ran the headline "French president's 'mistress'" over the picture of Gayet in a revealing red dress.

The newspaper said he was "facing a new crisis" and added for good measure: "Battling record unpopularity levels, the last thing the Socialist president needs is another scandal between the sheets."

Several newspapers referred to the fact that Closer had published topless pictures of Prince William's wife, Kate in 2012, but they said the circumstances were different.

Many of the British papers noted though that, as the Daily Telegraph put it, "affairs are nothing new in French presidential history".

They noted the extra-marital affairs of former presidents Jacques Chirac and Francois Mitterrand, who even had a daughter born to a mistress.

The left-leaning Guardian was sympathetic towards the socialist French president, reporting that Hollande had "enjoyed a rare moment of support and sympathy from across the political spectrum".

The paper, which has led calls to reform its raucous tabloid rivals in Britain, was largely responsible for exposing the phone-hacking scandal at Rupert Murdoch's now defunct News of the World.

It too noted that "presidential affairs are the rule rather than the exception in France".

The right-wing Daily Mail website meanwhile carried a string of partially naked pictures -- with strategically placed blacked out areas -- of Gayet in her "sexually charged screen roles."

But it also had an article on France's privacy laws entitled: "How the French elite keep public in the dark."