As things stand, the three top candidates in the first round of the presidential election on Sunday could represent parties outside the duopoly of centre-right and centre-left which has governed France since the end of the Second World War.

Imagine a British general election in which the three leading places were taken by the Lib Dems, Ukip and the Socialist Workers’ Party.

Only the top two candidates go forward to the second round run-off on 7 May. The final opinion polls suggest that four politicians — from the unknown centre, the far-right, the hard left and the discredited ex-Gaullist centre-right — have a chance of making the cut.

For several weeks, it seemed likely that the second round would be contested by the Front National leader Marine Le Pen and the 39-year-old founder of a one-year-old political start-up, the militant centrist Emmanuel Macron.

Both are now at around 23-24 per cent in the first round opinion polls. In the second round, the polls suggest, Mr Macron would crush Le Pen by 60 per cent to 40 per cent.

The Macron-Le Pen match-up is still possible but no longer certain. The last phase of the campaign has seen an extraordinary surge of support for an eloquent champion of the hard left, Jean-Luc Mélenchon (a harder left Gallic version of Jeremy Corbyn, with a sense of humour).

The final days have also seen a partial recovery by François Fillon, the former centre-right prime minister who had once seemed certain to be the next President of the Republic. Mr Fillon, who is accused of embezzling parliamentary funds by paying his wife to do nothing, is the only member of the leading quartet who represents a traditional “party of government”.

Both Mr Fillon and Mr Mélenchon are now credited with around 19 per cent of the vote. Seven other candidates range in the polls from 0.5 per cent to a calamitous 9 per cent for Benoît Hamon, candidate of the ruling Socialist party.

Predictions for the ultimate result on 7 May have therefore become an electoral Rubik’s Cube. Marine Le Pen would be unlikely to beat Mr Macron or Mr Fillon. She might triumph, however, in a one-on-one with Mr Mélenchon. Mr Macron v Mr Fillon would be close. Mr Mélenchon would lose to either man.

From the point of view of Jewish voters in France, there are only two comfortable choices in the leading quartet — Mr Macron and Mr Fillon. Even Mr Fillon is accused by some Jewish activists of links to an ancient Catholic-bourgeois strand of French antisemitic opinion. Mr Mélenchon is fiercely “anti-racist” but fiercely pro-Palestinian. Mr Macron, a former employee of Rothschilds, is pro-Israeli but critical of the present government in Jerusalem.

Ms Le Pen is, it turns out, her father’s daughter. In the final weeks of the campaign she undid seven years of cosmetic moderation by stating that the mass-arrest of Jews by French police and gendarmes in 1942 was not a stain on French history.