They cheered, clapped and chanted his name, but nothing could disguise the despondency overshadowing Manuel Valls’s presidential bid as he rallied supporters for the last time before the Socialist primary begins Sunday.

Unusually, the former prime minister enjoyed the advantage of a packed house — thanks to the choice of venue, the small Trianon theatre near Montmartre, where Nicolas Sarkozy’s wife, the model and singer Carla Bruni, has performed.

Mr Valls rose to the occasion, delivering a rousing speech lasting more than 90 minutes to the thousand-strong crowd, ending an otherwise lacklustre campaign, during which he appeared tense and sometimes tetchy in TV debates.

He was rewarded with roars of “Manuel President”, but even his most ardent supporters acknowledge that he has only the slimmest chance of victory.