Liberal Democrat leader Tim Farron has indicated that the calamitous environment of British politics presents an “historic opportunity” to build a new political party or alliance on the centre-left, involving both the Labour Party and his own MPs.

With Labour experiencing a “moment of peril” – as one leadership contender described it last week – and bitter in-fighting leading to growing speculation about a split, the Lib Dem believes there is now a timely chance to create a new opposition to the Conservatives – either through an alliance, a grouping of MPs or the creation of a new party.

In an exclusive interview with The Independent, Mr Farron, who has committed his party to fighting the next general election on a platform of derailing Brexit, said he’d had “off camera” conversations with other progressive politicians during the EU referendum campaign. Asked whether he was open to creating a new political party in Britain, Mr Farron said: “I think we write nothing off.”

“My job is to defend the Liberal heritage of our movement… but, I think we’d be betraying the legacy of Gladstone, Grimond, Charles Kennedy and others if we were to just defend our tribal interests when we have a historic opportunity to find a polar alternative to the Conservatives, which could make the 21st century one which is a lot more progressive than the 20th was.”

His remarks come after the Green MP Caroline Lucas and Natalie Bennett, the party’s leader, wrote to the leaders of centre-left parties in Britain and urged them to club together in the event of a snap election following the appointment of Theresa May as Prime Minister. The letter, which was sent to Jeremy Corbyn, Mr Farron and Leanne Wood, leader of Plaid Cymru, said: “There is an urgent need to make a stand against any austerity and the slashing of environmental legislation, human and workers’ rights that may come with Brexit.”

When asked who might form part of this “progressive alliance”, Mr Farron said he had talked to Ms Lucas directly. But he dismissed the use of letters to communicate with potential collaborators. “The Liberal-SDP alliance was not formed on the basis of a bunch of letters press released to newspapers. It was about getting to know one another and looking at what was in the interests of progressive politics. I suspect that’s the kind of thing we’re talking about now,” he added. “But where I absolutely have common ground with Caroline Lucas and others… is on the issue of electoral reform.

Brexit protest: Thousands march in London Show all 12 1 /12 Brexit protest: Thousands march in London Brexit protest: Thousands march in London A woman poses with a home-made European Union flag as Remain supporters gather on Park Lane in London to show their support for the EU in the wake of Brexit PA Brexit protest: Thousands march in London Remain supporters demonstrate in Parliament Square PA Brexit protest: Thousands march in London Tens of thousands of people gathered to protest the result of the EU referendum PA Brexit protest: Thousands march in London A majority of people in the capital voted to remain in the European Union Reuters Brexit protest: Thousands march in London Protesters chanted: “What do we want to do? Stay in the EU” PA Brexit protest: Thousands march in London The march follows a similar rally in Trafalgar Square that was cancelled due to heavy rain – but which tens of thousands of people turned up to anyway Reuters Brexit protest: Thousands march in London Britain voted to leave the European Union in a referendum by 52 per cent to 48 per cent Reuters Brexit protest: Thousands march in London But support for the Leave campaign in urban areas and among young people was significantly lower Rex features Brexit protest: Thousands march in London Marchers gathered at Park Lane at 11am and marched towards Parliament Square PA Brexit protest: Thousands march in London Some protesters held up baguettes in a display of affection for our continental neighbours PA Brexit protest: Thousands march in London The disparity between different parts of the country has promoted a four million signature petition calling for a second referendum and even a renewed push for Scotland to cede from the UK PA Brexit protest: Thousands march in London The event’s organiser, King’s College graduate Kieran MacDermott, wrote: “We can prevent Brexit by refusing to accept the referendum as the final say and take our finger off the self-destruct button" Reuters

“The whole current scenario reminds us that the Labour and Tory parties in particular are completely and utterly false and uncomfortable coalitions. You’ve got the far left and the soft left of the Labour party… and in the Tory party you’ve got English nationalists versus pragmatists and even some liberals within the Tory party. In any other democracy in Europe those people wouldn’t be in the same party as one another – and quite a few would be in the same party as us.

“My sense is that one of the many outcomes of the referendum is the fact that progressives have rather enjoyed one another’s company on the campaign trail… there are loads of people out there who you realise in this most calamitous and febrile set of circumstances you share a lot more in common with them than the fact you want to be in the European Union. So realignment is a real, real possibility”.

But, he added, it is too early to tell if the election would be contested with such an alliance. “A form of any kind of movement does depend upon what happens in the Labour party,” Mr Farron said. “The main situation will be how members of the Labour party relate to Liberal Democrats. We have to respect what’s going on in the Labour party at the moment and see what happens. My genuine sense is that I can’t see a happy ending for them.”

Mr Farron, who believes his party could be the gel that holds any centre-left movement together, added: “My job is not to be a home wrecker… my job is to be a home provider, a home builder.”

Asked whether he’d opened talks with members of other parties, Mr Farron refused to name any specific individuals but replied: “You saw who I shared a platform with during the referendum. We talked to those people off camera, shall we say, and those conversations are things I think we should continue.”

On Friday Mr Farron’s party, which suffered huge losses at the general election in 2015, hailed its best night of local election results “in a decade”, after the Lib Dems picked up four council seats in town hall by-elections across the country, taking seats off Ukip and the Conservatives in Newquay and North Norfolk respectively. Gains were also made at the expense of independent candidates in Cornwall and Wiltshire.