Dr Andrew Murrison is Conservative MP for South West Wiltshire.

So far, so funny, Conservatives for Corbyn. But gloaters should be careful, and not because of pieties around the need for an effective opposition or fears that, unchallenged, the Conservatives will turn to fat.

No, the threat to the next Conservative majority and to intermediate elections running up to 2020 will be, as ever, a challenge on the middle ground. In that extraordinary way politics has of delivering the unexpected, a Corbyn victory next month might deliver it. Because if, as seems likely, a significant chunk of the Labour parliamentary party from the bit that’s not mortgaged to the unions proves incapable of stomaching the retro politics he advocates, there will be plenty looking for somewhere to go.

And they won’t have far to look.

The elevators in the Commons have a little sign telling you the maximum capacity is eight. How funny, I said to a Lib Dem friend the other day as the lift doors closed, you could hold your party meetings in one of these, having just eight MPs and all. You could even say the Lib Dems have been ‘elevated.’ How he laughed!

The Lib Dem eight is a sorry crew jammed dyspeptically between the SNP and the Ulstermen on the opposition benches. It’s difficult to see them riding out five years under their leftist new leader on the margins of politics. Rather, after its coalition flirtation with the practical politics of doing useful things for actual people, the Lib Dems will revert to type. Their interest in process over substance, of course, extends to party formation and reformation at which they and their progenitors have a century of experience.

Eyeing refugees from a Corbyn Labour party, the Lib Dems will surely be reaching deep in the freezer beneath the tofu and vegetarian pizza to fish out what Paddy Ashdown called ‘The Project’. The much-diarised brainchild of his hat-eating Lordship was, if you recall, the union of the left of centre to lock the Tories out of Number Ten. I’d be surprised if, from his home in his old Yeovil fastness – now, like the rest of the South West, assuredly Tory – Paddy isn’t working out how The Project can absorb Labour’s agonies, rejuvenate the Lib Dems and realise his dream.

The UK’s last big realignment on the political centre, the rise of the SDP-Liberal Alliance may look inauspicious through the retrospectoscope but it put the wind up Conservative Party managers in the 1980s. The emergence of a credible centrist bloc appealing to voters who delivered three walloping Blairite majorities and capable of a post 2020 accommodation with the SNP should worry them now.

The twin delights of Jeremy Corbyn’s ascendancy and the ‘elevation’ of the Lib Dems may be drawing battle lines for 2020 in an unexpected and hugely unpredictable way.