WHAT explains the sudden rise of Benoît Hamon? A few months ago he was a nondescript former education minister. Now he is favoured to beat Manuel Valls, the centrist who was France’s prime minister until last month, in a run-off primary on January 29th for the Socialist presidential nomination, having won the first round a week earlier. A proud leftist, he would probably lead his party to a crushing defeat in the election in April.

The party’s true believers were fired up by Mr Hamon’s ideas. He says France can cope with digital disruption by adopting a universal basic income, eventually to be worth €750 ($805) a month per adult. He would cut the 35-hour working week even shorter and levy taxes on the use of robots. (After all, robots can’t vote.) Why, though, didn’t the party’s centrists turn out for Mr Valls? Unfortunately for him, it looks as if they have abandoned the party altogether.

To see where French centrists have gone, one needed to take a trip to a pig farm in Brittany last week, where a crowd of reporters trailed behind Emmanuel Macron, an independent candidate and ex-minister. Mr Macron had forgotten his rubber boots, but strode gamely into the dung of a low-roofed shed to cuddle a piglet on national TV (pictured). The 39-year-old, a former banker, has only been in politics for a couple of years. Yet the media cover him incessantly, and polls put his support at 21%—a few points behind the two front-runners, the nationalist Marine Le Pen and the centre-right’s François Fillon.

The trip was a reminder that, despite anxieties about terrorism, Islam and immigration, French voters are most concerned about the economy. Mr Macron paid a visit to a regional travel company, highlighting how a reform he introduced in 2015, liberalising transport, created a new industry of inter-city coaches. The boss of one firm, Ouibus, said the reform led him to create 500 extra jobs.

The economy, after years of gloom, shows some signs of recovery. Overall annual GDP growth is only a notch above 1% and unemployment is still more than 9%. But that rate has drifted down since August as private firms started hiring. Two years of fiscal stability, a weak euro and open spigots at the European Central Bank have lifted business spirits. On January 24th one measure of managers’ confidence showed it higher than at any point in five years. Yet structural problems are not close to being tackled. Official figures try to disguise it, but France’s public finances are ropy. Didier Migaud, the national auditor, last week called them “fragile and vulnerable”, casting doubt on the government’s claim that the deficit will soon fall within the euro zone’s 3%-of-GDP limit. Some voters on the centre-right might be drawn to Mr Macron, too. Mr Fillon, the Republican candidate, has struggled this week to explain what work his wife performed while he was employing her as a political assistant, at an expense to the public of about €500,000 over a decade. His economic policies are also hard for many to swallow. He has backed away from proposals for radical changes to insurance and the national health system that critics likened to privatisation. He has also refrained from naming some of the figures expected to join his cabinet—such as Henri de Castries, an ex-boss of AXA, an insurer—for fear of looking too plutocratic.

Mr Fillon talks of cutting corporate and wealth taxes, while raising sales taxes, lengthening the working week to 39 hours and lowering public spending (which accounts for 57% of GDP). He would also, over five years, scrap 500,000 government posts. He is widely called “Thatcherite”, not a term of endearment in France.

Beyond him is Ms Le Pen of the National Front, who leads in the polls. She is pursuing a strategy of cultivating blue-collar workers in the industrial towns of eastern and northern France. She attacks trade, globalisation and the liberal policies of Mr Fillon, while claiming that strong borders, and pulling out from the euro, would end “economic suffocation”.

This leaves Mr Macron as the only candidate in the economic centre. The Republican and Socialist candidates might yet return to it. If not, the prospects for Mr Macron will be unexpectedly bright.