Leading figures in the ruling French Socialists have rushed to avoid a damaging split over their candidate in the spring presidential election.

Alarm bells sounded after Prime Minister Manuel Valls suggested he might stand against President Francois Hollande in party primaries.

A government spokesman warned Mr Valls would have to resign in order to do so.

Meanwhile, Francois Fillon became the conservative candidate after triumphing in his party primaries on Sunday.

With nearly all the ballots counted, he had won 66.5% to 33.5% for his run-off rival, Alain Juppe.

A new opinion poll suggests he would easily beat the far right’s Marine Le Pen in the actual election.

According to the Harris Interactive poll for French parliamentary TV (in French), Mr Fillon would lead the National Front candidate by 26% to 24% in the first round, then win the run-off against her by 67% to 33%.

The same poll indicates that either Mr Hollande or Mr Valls would win just 9% for the Socialists, leaving them to trail both the far left and the centrists.

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‘Fragmentation fever’

Mr Valls said on Sunday that he would not rule out running against Mr Hollande in the primary, telling the Journal du Dimanche he wanted to dispel the idea that the left had “no chance” of retaining power.

The two men are expected to have lunch together on Monday at the Elysee Palace, as they normally do each week, French media report.

But government spokesman Stephane Le Foll stressed that Mr Valls would need to resign in order to stand for the candidacy.