Pity the Liberal Democrats. Not a day passes without op-eds advocating a new party of the centre-left. Labour, they assert, is beyond repair. But rarely do their writers pause to note the alternative which already exists.

When Jeremy Corbyn became Labour leader, some predicted a Lib Dem surge would result. Former cabinet minister Jack Straw spoke of “Lazarus being raised from the dead”. But despite Labour’s parlous state, the corpse has little stirred. Tim Farron’s party gained more council seats than any other in the 2016 local elections (45). But its national poll ratings remain frozen at around 8 per cent. This despite the EU referendum defeat providing an opening for the UK’s most europhile party. Farron swiftly - and smartly - pledged to fight to overturn Brexit. But few of “the 48 per cent” have flocked to the Lib Dems.

Part of the explanation is provided by the curt answer Theresa May gave Farron during her first Prime Minister’s Questions: “my party is a little bigger than his”. With a mere eight MPs (the same number as the Democratic Unionist Party), the Lib Dems struggle for seriousness in the UK’s ruthlessly majoritarian culture. Journalists who hastily mugged up on the party after the formation of the 2010 coalition have once again erased it from their minds. The Lib Dems’ five years in government are now regarded as a fleeting exception to monopolistic rule.

Farron’s intention was to win over the left-wing voters left cold by Labour’s timidity. Early in the new parliament, he opposed the welfare reform bill (unlike the opposition frontbench) and military action in Syria. But Corbyn’s subsequent election blocked this escape route. Farron’s critics suggest the party would have been better off electing a centrist leader in the mould of Nick Clegg.

But whoever took the helm faced a formidable task. After running to the left of Labour for successive elections, before partnering with the right, the Lib Dems managed to unite disparate groups of voters in loathing. Some contend that only a name change offers hope for recovery (an option Farron’s team have rejected).

Yet the Lib Dems are worthy of more attention than their stagnant state suggests. If Labour is to re-enter government it needs Lazarus to rise. In the south-west, where the Conservatives now hold 51 of 55 seats, the Lib Dems remain the main opposition. Just as it was their collapse which enabled the Tories’ majority, so it is only their revival which will reverse it. Though Corbynites speak ambitiously of advancing in the south-west (which contains rarely acknowledged deprivation) this, at very best, is the work of a generation, not four years.

Though the Lib Dems and Labour are frequently framed as rivals, their fortunes have more often than not been intertwined. In 1997, 2001 and 2005, a healthy centre-left (and waves of tactical voting) kept the Conservatives at bay. In 2015, Lib Dem failure was not accompanied by Labour success. As long as both sides are content to mock each other, that pattern risks enduring.