Tim Farron's pledge to campaign to take the UK back into the EU at the next general election has attracted 10,000 new members to the Liberal Democrats, the party has claimed. The Democrats have even claimed that some of these new members voted Leave at the 23 June EU referendum and signed-up because they were "horrified" by the Brexit vote fallout.

"I don't blame those who were duped – I blame those who lied. If the Conservatives had a shred of decency, they would set about fixing the economy they broke," Farron said.

"Yet the Chancellor [George Osborne] shrugs that it is not his responsibility to have a Brexit plan – even though he and David Cameron were the brains behind this risky referendum – while Boris Johnson has sounded, perhaps more predictably, clueless.

"People can also see the Labour leadership did not put their back into the fight – when history called they did not step up to the mark.

"As the other two parties fight among themselves, people are starting to recognise that only the Liberal Democrats are fighting for their European future."

The comments come as the Conservative Party holds its own leadership election in the wake of David Cameron's announcement that he is to resign as prime minister. The Labour party is also facing upheaval after many of its heartlands across England and Wales vote Leave.

Remain campaigner Jeremy Corbyn has faced mass-resignations from his shadow cabinet and overwhelmingly lost a vote of no confidence from Labour MPs. But the left-winger, who attracted almost 60% of the vote in Labour's 2015 leadership election, has vowed to stay on.

"Labour has the responsibility to give a lead where the government will not. We need to bring people together, hold the government to account, oppose austerity and set out a path to exit that will protect jobs and incomes," Corbyn said in a statement on 28 June. "To do that we need to stand together. Since I was elected leader of our party nine months ago, we have repeatedly defeated the government over its attacks on living standards."

He added: "Last month, Labour become the largest party in the local elections. In Thursday's referendum, a narrow majority voted to leave, but two thirds of Labour supporters backed our call for a Remain vote.

"I was democratically elected leader of our party for a new kind of politics by 60% of Labour members and supporters, and I will not betray them by resigning. Today's vote by MPs has no constitutional legitimacy.

"We are a democratic party, with a clear constitution. Our people need Labour party members, trade unionists and MPs to unite behind my leadership at a critical time for our country."