Media playback is unsupported on your device Media caption Tim Farron: Britain needs a party that is progressive, moderate and liberal

The election of Jeremy Corbyn as Labour leader means the Lib Dems are now the only "credible" alternative to Tory rule, Tim Farron has told activists.

The Lib Dem leader told a packed hall of supporters at the start of their party conference in Bournemouth: "This is our moment".

He said Labour had "left the playing field" and it was up to the Lib Dems to fill the gap and take on the Tories.

The party is targeting Labour voters dismayed by Mr Corbyn's leadership.

It plans policy announcements this week to show that Mr Farron is more credible than Labour on the economy.

'Win again'

But Mr Farron has played down suggestions that "moderate" Labour MPs are ready to defect to his party, which is still reeling from losing all but eight of its MPs in May's general election.

The theme of the conference, summed up in a Twitter hashtag, is LibDemFightback.

The party claims it has attracted record numbers of activists to its annual conference, including many of the 20,000 people who have joined since the election.

Image copyright PA Image caption The Lib Dems are targeting Labour voters dismayed by Jeremy Corbyn's leadership.

The Lib Dem leader, who is due to deliver his keynote speech to conference on Wednesday, opened the event with a rallying call to activists, telling them: "I am tired of losing. Let's win again."

He received a standing ovation from activists who had been warmed up by a performance by the London International Gospel Choir.

Mr Farron, who was elected to replace Nick Clegg in July, condemned the "fantasy economics" of by Mr Corbyn and shadow chancellor John McDonnell and accused Labour of "nostalgia" for the student politics of the 1980s.

'Our moment'

He said: "If Labour aren't interested in standing up to the Tories and providing a credible opposition, that's their funeral.

"The Liberal Democrats will fill that space. Radical and liberal and responsible too."

Image copyright Getty Images Image caption The Lib Dem leader told supporters it was up to their party to fill the gap and take on the Tories

The Lib Dem leader warned the audience that we "once again see the prospect of a decade or more of Tory rule, and it fills us with dread".

He added: "When the tectonic plates of politics move, they sometimes move immensely quickly - that is what is happening now.

"These are momentous and historic times, history calls us, we will answer that call.

"Britain needs a party that is progressive, moderate and liberal. We are that party. This is our moment."