Nick Clegg said his offer to quit as leader of the Liberal Democrats a year before the party's "disastrous" election night would not have made a difference to the results if accepted.
Giving his first interview since he stood down as the Lib Dem leader after the party finished with only eight seats, Clegg confirmed he would have quit last May had he felt it "would have helped in election".
Reports say Clegg discussed quitting as party leader following the Lib Dems' humiliating results in the European and local elections in May 2014.
He told one colleague: "If I believe – and I am very close to thinking it – I am the problem and not the solution, I have to stand to one side," reported the Guardian.
Speaking to LBC Radio, Clegg said he believes a change in leadership so soon before the general election would not have stopped the SNP "surge".
He said: "The beginning of the campaign felt like it was shaping up to be quite a traditional right/left argument, to which at least we were a plausible centre-ground alternative.
"I can't quite pinpoint it, but maybe 10 days or so before Election Day, all of us really felt this seeping fear in England of a Labour government dancing to the tune of [the] SNP, which really chilled the English heart.
"You really could see lots and lots of people who would have traditionally voted for the Liberal Democrats basically playing it safe and saying, 'No no, that's one thing we absolutely don't want,' and the best guarantee against that was for them to vote Conservative even if they haven't voted for them before."
Clegg also admitted the first thing he did after he saw the exit poll, which predicted the Lib Dems would only win 10 seats, was reach for a cigarette for the first time in more than two years.
"I've stopped again now, so don't worry. Sanity has been restored."
He added: "Like everyone else, I was pretty blindsided by that exit poll," he said. "Initially, like everyone else, I thought that just can't be right, but I did instantly think to myself even if we get twice as many as that exit poll says, it is still a much worse night than I could have hoped for."
Despite the result, Clegg said he has no regrets in forming a coalition with the Tories following the 2010 election.
"I don't regret it at all, not for one millisecond doing the right thing," he said.
"I haven't destroyed the party. Liberalism will survive and the Liberal Democrats will bounce back."