LONDON — Sir Vince Cable has insisted that Britain may never leave the EU, once the public is faced with the stark choice of staying in or crashing out without a comprehensive Brexit deal.

In a wide-ranging interview with Business Insider, the former Business Secretary also:

Rubbished widespread speculation that he plans to stand down as leader of the Liberal Democrats before the next general election.

Promised not to prop up a minority Labour or Conservative government.

Said he plans to mop up millions of "moderate" voters as Lib Dem leader.

Defended comments comparing Theresa May's party conference speech to Mein Kampf.

The newly re-elected MP for Twickenham is set to be elected the party's new leader later this month but recent reports suggest that plans are already in place for Cable to hand over the role to a younger colleague before the next general election in 2020.

Speaking to BI on Thursday, the former Business Secretary insisted that he would serve as party leader beyond 2020 and vowed to transform the Liberal Democrats into a "constructive opposition" if elected.

"I am clear that I am not just there as a stopgap or a caretaker," Cable said. The veteran MP announced his candidacy last month and is currently on course to becoming leader with no other Lib Dem figures in the running for the position.

"I am prepared to serve this out and fight the next election whenever this is. I have some very good colleagues but that's not the point. I am not just here as a temporary caretaker."

Cable was also keen to rule out taking the Lib Dems into coalition with either the Conservatives or the Labour Party under his leadership — a stance outgoing leader Tim Farron reiterated throughout the election campaign.

"We are not remotely contemplating coalition with the current Labour Party or with the Conservatives," he told BI.

"We're in a fundamentally different place on the biggest issues of the day of which Brexit is the most important. When you're in fundamental disagreement you can't meaningfully talk about coalition."

Cable made it abundantly clear that the party is not interested in formal deals, but did not dismiss reports published this month claiming that the 12 Lib Dem MPs in Westminster would be prepared to vote with the government on a case-by-case basis. "We are talking about being a constructive opposition," he said.

"Obviously, there will be particular issues where you can make an impact in that way. But we are not talking about coalitions or propping up this government or Labour for that matter."

"We have a historically important role"

Cable was coy about his imminent coronation as party leader. "Well I am not the leader yet and we need to respect the process," he told us. But he was explicit in where he thinks the potential for Lib Dem success lies: Brexit.

"There is a vast opening in British politics. We are very polarised between the hard right and hard left. There are millions of people with moderate views who are looking for a party that is shaped like the Liberal Democrats but haven't been supporting us. My job is to turn that potential into political support. I don't underestimate the difficulty given how the British voting system works but that is the challenge, but it's also very clearly an opportunity."

"I hesitate around the word 'centre' when referring to politics," he added.

"We are no longer dealing with the old right old left spectrum in the same way. There is a sense I think of extremes dominating and the good things in British society are being crowded out by extreme arguments — and it centres very much around the Europe issue. I think people are beginning to see that this hard Brexit option which is being promoted both by the government and the Labour Party is profoundly damaging and people are desperately trying to find a way of mitigating the damage, or indeed stopping it. That's where we have a historically important role."

I put to the former cabinet minister the argument that neither "stopping" not delaying Brexit is of interest to the British public. After all, his party under Farron's stewardship ran a campaign centred on holding another nationwide referendum on Britain's membership of the European Union, but won a smaller share of the vote compared to 2015 when it collapsed. This was despite early widespread talk of a Lib Dem "resurgence" fueled by staunch Remainers.

"I think it is right to aim for Britain remaining in the single market and customs union and retaining all of the collaborative arrangements around research and environmental standards. They are things we should be fighting for.

"But it may be that at the end of it, we are faced with a stark choice between crashing out of the EU with a no deal or a very bad deal, or on the other hand going back to membership. That's why my party argues that we should have a further vote on this. That didn't resonate with voters at this year's election. We all know that. It was premature and people thought we were harking back to the last one. But in two years time when it's very clear what the economic impacts are I think the public will welcome that kind of option."

So he thinks Britain could end up remaining a member of the EU?

"It's certainly a possibility. It's not yet a probability."

"I was simply making a statement of fact"

Cable is not yet the leader of the Liberal Democrats but already his newfound political profile has experienced a moment of controversy. The veteran MP raised eyebrows in a recent interview with the New Statesman by comparing Theresa May's use of the phrase "citizens of nowhere" in her 2016 Conservative Party conference speech to Mein Kampf, the autobiography of Adolf Hitler:

"I thought that particular phrase was quite evil. It could’ve been taken out of Mein Kampf. I think that’s where it came from, wasn’t it? ‘Rootless cosmopolitans’? It was out of character for her."

Cable told BI that he did not regret using the comparison, insisting it was a "quite reasonable" thing to say.

"Well, I was simply making a statement of fact," he said. "I think the phrase 'rootless cosmopolitans' actually comes from that source. I did say in the following sentence that it was very out of character and that Theresa May is not extreme in that way and I made that very clear.

"Anyone who actually read what I said rather than the headlines would have realised that what I was saying was quite reasonable."