Realignment of Britain’s political party system may be on the way because of “civil war” within the two major parties and the threat of a chaotic no-deal Brexit, Liberal Democrat leader Sir Vince Cable has said.

Sir Vince said that “reasonable” politicians from all parties wanted to avoid the possibility of the UK crashing out of the European Union without a withdrawal agreement.

He said “the conditions are there” for change in the traditional line-up of parties, and made clear that he was taking steps to prepare the Lib Dems for working with people outside the party.

Speaking to BBC Radio 4’s Today programme, Sir Vince revealed that he missed a vital Brexit vote in the Commons on Monday in order to take part in a “confidential political meeting on relevant subjects”, but declined to give details of who he was talking with.

Asked whether he believed a political realignment was coming, Sir Vince said: “It does look as if it may happen.

“The problem is the Conservative Party is now hopelessly divided in civil war and there is a similar situation in the Labour Party for different reasons.

“A lot of people in both the major parties are talking openly about breaking away and people outside are trying to encourage it.

“I think the public generally are fed up with the very dysfunctional nature of British politics.”

He added: “I certainly want my party to be more open and willing to work with other people. We recognise a new world is coming and I’m certainly over the summer going to be thinking about how we make ourselves more open and relevant to this new world.”

Sir Vince was speaking amid increasingly open rancour between hard and soft Brexiteers in the Conservative Party, and a day after prominent Jeremy Corbyn critic John Woodcock quit Labour.

He acknowledged that his absence from Monday’s votes on the Customs Bill had been “a mistake”, but said Prime Minister Theresa May was saved from defeat by a number of Brexit-backing Labour MPs who voted with the Government.

Sir Vince warned that the risks of a chaotic no-deal Brexit were now “significantly higher” and accused some Conservative MPs of actively trying to bring it about.

“It would be very, very damaging because significant trade barriers would be created,” said the Lib Dem leader. “I think there are people in the Conservative Party who are egging on that outcome and hope to be able to blame the European Commission for it.

“All the evidence we have … is that it would be massively disruptive and significant losses would be imposed on the UK economy and the most vulnerable people are often the people in the deprived parts of Britain which voted for Brexit.

“Ten years ahead, no doubt all this would be sorted out, but it would mean we enter a very difficult economic period with significant economic damage.

“I don’t think reasonable people on all sides of this argument really want that to occur.”