The Liberal Democrats leader has suggested he would be open to forming a new centre-left party as Labour MPs grow increasingly frustrated in their attempts to remove left-wing leader Jeremy Corbyn.
Tim Farron said there was an opportunity to create a new party or alliance to oppose the Tories and when asked if he was open to such a movement, told the Independent: "I think we write nothing off."
He claimed he has already had "off-camera" conversations on the issue with politicians from other parties during the EU referendum campaign, when tribal divisions were set aside as the centre-left broadly came together to unsuccessfully back Remain.
The Lib Dems are currently at a low having suffered a disastrous 2015 general election, leaving the party with just eight MPs.
Farron told the newspaper: "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.
"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."
Farron said progressive politicians "rather enjoyed" each other's company during the referendum campaign.
"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," he said.
The Green Party has already called on Labour, the Lib Dems and Plaid Cymru to form a "progressive alliance".
But Farron said any move depended on the outcome of the Labour leadership contest.
"The main situation will be how members of the Labour Party relate to Liberal Democrats," he said.
"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."
Farron's comments come with Labour in crisis following the resignations of most of the shadow cabinet that led the party into the EU referendum, and after 172 MPs backed a no-confidence motion in Corbyn, with just 40 supporting their leader.
Owen Smith and Angela Eagle are now challenging Corbyn in an active leadership contest.
But launching his campaign yesterday, Smith insisted he did not want to see the party split.
At an event in his Pontypridd constituency, the former shadow work and pensions secretary said: "It cannot happen, it will not happen.
"If I've got anything to do with it, never on my watch will this party split.
"It won't split because we cannot afford it to split and, more important than that, working people in this country cannot afford the Labour Party to split."