And can he expand new Lib Dems support beyond Europhiles?

In the week when the Brexit talks finally got down to business, the Lib Dems acquired a new leader to head up the fight to – well, that’s the first question: what exactly are the opponents of the government’s Brexit policy (which itself is hardly perfectly defined) themselves advocating?

Vince Cable is already seeking to ride more than one horse on Brexit, advocating both that Britain remain within the Single Market and the Customs Union, and also that there should be a second referendum once a deal is in place, asking the public whether we’d rather stay in the EU after all, thanks very much.

One could argue that these are not contradictory and in a sense, they’re not: remaining in the EU’s key structures is most easily achieved by staying within the EU, and that if de jure membership isn’t possible then de facto membership (bar the influence and appointments) is the next best thing. On the other hand, those who want to keep Britain within the EU might not wonder whether trying to get the very soft Brexit doesn’t work counter to that higher goal.

Whether a Brexit-exit is even possible remains a contentious question. Several authorities, both EU and UK, have voiced the view that Article 50 can be withdrawn. This, however, tends to fly in the face of text and the logic of the Article. If notice could be withdrawn, what’s to stop a member yo-yoing until they get the deal they want? More pertinently, if it is revocable, why doesn’t it say so when it is so explicit about when the treaties cease to apply to the withdrawing member? Either way, without a judgement from the ECJ, no-one can know for sure.

But for the Lib Dems, and for now, that’s not a concern. Britain hasn’t experienced a conversion but there are more than enough who are very keen to Remain (or who are angry about Brexit if remaining isn’t possible), for a smaller party to chase. Some might point out that this was the same strategy that Farron tried in the Spring and which failed (although not for Cable himself). To some extent that’s true but Sir Vince might be more optimistic of making it work, partly because he’s a more authoritative figure and partly because he’ll be able to work in the light of more experience.

Opposition to Brexit (or support for the softest possible Brexit), however, can only be part of the Lib Dems’ recovery plan. To get back to where they were pre-2010, they’ll need to be seen as relevant again, which across large parts of the country, they’re not.

There are many stats which tell the same story. That they lost their deposit in 375 seats is one but perhaps the best illustration is that the average vote per Lib Dem candidate in 2017 was just 3771: it’s not been lower than that since 1886, when William Gladstone was leader and the franchise much more restricted.

You would think that conditions now ought to be ideal for a centre party. Labour has marched off to the left and looks set to stay there for the foreseeable future given the hugely increased authority Corbyn has received from Labour’s – his – campaign and election result. The Tories are weighed down by the Brexit talks and the internal divisions that’s causing, on top of an economy that might be stuttering and public services struggling after seven years of spending restraint. UKIP has served its purpose and even the SNP has peaked.

And they are ideal. The question is whether he can succeed where Farron failed and establish himself as a more credible opposition than Corbyn. He has form, of course. His brief acting leadership after Ming Campbell ’s resignation was notable for his ‘Stalin to Mr Bean’ quip to Gordon Brown. He also cultivated useful links with the media, notably Robert Peston. Getting in front of the camera as often as possible must be a key aim.

Which brings us back to Brexit. Barring something completely unexpected, Britain’s withdrawal from the EU will dominate British politics for at least the next 18 months. Labour’s internal divisions and particularly Corbyn’s disinterest in and ambivalence toward the EU should give Cable a tremendous platform to put an opposing case to the government, as well as to link it to the economy and potentially the NHS, social services and other issues.

The stakes are high. An effective performance from the Lib Dem team, led by Cable, could well see the party back into the high-teens or twenties. The coalition of ardent Remainers and pragmatic free marketeers is a sizable one but not one being particularly courted elsewhere at the moment. On the other hand, were he to fail as his two predecessors did, the future for his party would be grim indeed. Nature abhors vacuums and someone must fill the one in the centre. Logic suggests that should be the Lib Dems. But then logic has had an unusually weak relationship with politics these last few years.

David Herdson