Liberal Democrat leader Jo Swinson claims Jeremy Corbyn is “not fit to be Prime Minister”.
She adds she would not back him – “under any circumstances” – to lead an interim government.
Ms Swinson also said the same about Boris Johnson.
She said the public “deserves a better choice”.
Ms Swinson said: “Jeremy Corbyn is not fit to be prime minister. Boris Johnson is not fit to be Prime Minister.
“Well he [Corbyn] doesn’t have the numbers. If you add up the numbers even without the Liberal Democrats, he’s far short of it.
“And let’s remember why he is far short, part of that is because there are people who were Labour MPs who have left the Labour party because their failure to deal with anti-Semitism.
“We are not talking about something that is irrelevant or a minor problem about something, we are talking about the fundamental value of whether people are treated with equality.
“So there’s very good reasons people have for saying why they wouldn’t back Jeremy Corbyn and I think in those circumstances we need to find a solution that works, and I think there’s a wide range of people who could lead such a government.
“I’ve put forward Ken Clarke or Harriet Harman – but if you look at others who have been long respected MPs there’s people like Margaret Beckett.
“There are lots of people who are a little bit above party politics who would step in.”
Ms Swinson believes “it is entirely possible” that the Liberal Democrats could secure a majority at the next election, and said she is “hopeful” for more defections.