The Liberal Democrats were "killed" by the inaccuracy of the pre-election opinion polls, Paddy Ashdown has claimed.

Just eight Liberal Democrat MPs remain in the House of Commons after polling day, with many of their one-time coalition Cabinet members losing their seats.

Having said he would "eat my hat" after a learning a shock exit poll predicted a significant Conservative victory, the party's former leader admitted he had been "blindsided" by the result.

The pollsters are facing an independent inquiry by the British Polling Council after almost every election poll during the campaign underestimated the Tories' lead over Labour.

In an interview with the Guardian, Lord Ashdown said: "We were absolutely blindsided, just like everyone else, except of course the good Professor Curtice (who was behind the exit poll) - hence my eat my hat comment.

"Actually what killed us was the inaccuracy of the (earlier) polls. If the polls had shown the real situation - the Tories with a clear lead over Labour - then the argument that we had to be there to moderate them would have had far greater traction.

"Paradoxically, the polls helped the Tories by magnifying the fear factor that they played so ruthlessly. The public feared Miliband/Salmond more than they feared a Tory majority. They are about to find out how wrong they were."

Lord Ashdown added he thought the victory was an "unexpected success" for David Cameron's party as much as it was an "unexpected disaster" for the Liberal Democrats, although the polls had forecast heavy losses for the party.

He also said the success of the SNP was "the creation" of Mr Cameron and said he felt "the Union was more at risk than at any moment in the last three centuries".

The race to be the party's next leader, following Nick Clegg's resignation, is expected to be dominated by Tim Farron and Norman Lamb.

Nominations will open on Wednesday. To get on the ballot a contender must secure the endorsement of 10% of MPs - now less than one person - as well as 200 members from at least 20 local Liberal Democrat parties.

The wider membership then elects the winner via an alternative vote system, with the verdict due on July 16.

Mr Farron said the party needed to "turn anger into action".

He told BBC Radio 4's Today programme: "I'm shattered by the results, if I'm honest. We saw our result coming through in Westmorland, it looked healthy, and everything else appeared to be carnage around us apart from a handful of colleagues and I'm not going to jump to enormously quick conclusions as to why that was the case.

"But certainly what I saw, you've got to take your hat off to them, was a very effective campaign run by the Scottish nationalists and it would appear the English nationalists, led by David Cameron, on the basis of fear of the other.

"And fear is a hugely motivating factor in elections, I'm sad to report, and what we've got to do is offer something far better than fear - unity, hope, values that draw us together.

"So it's not a case of being a bad loser, it's somebody who is determined not to be a loser again."

Mr Farron, who has said that he will decide in the coming days whether to challenge for the leadership, has been urged to run by the leaders of the Scottish and Welsh Lib Dems, Willie Rennie and Kirsty Williams.

"Tim is a committed liberal, a brilliant communicator, an outstanding campaigner and an inspirational leader," they said in a joint statement.

"With him as leader we can show that we are a compassionate, tolerant, internationalist, reformist party that looks beyond sectional interest to the greater good, to our children's future not just ours, that believes in partnership home and abroad, not division, that is liberal and democratic."