Jo Swinson has apologised for the Lib Dems’ decision to back austerity policies, including the bedroom tax, when the party was in power with the Tories.

The party leader, who served as a minister under David Cameron, was forced to admit the coalition’s cutbacks went too far when she faced a grilling by veteran BBC journalist Andrew Neil. 

Questioned repeatedly about whether austerity had worked, she said: “Clearly too much was cut.

“Clearly not enough was raised from taxation.

“Some cuts were necessary, but the shape of those cuts and certainly the balance between cuts and tax rises, I don’t think was the right balance.”

Asked specifically about whether she would apologise for supporting the so-called bedroom tax, Swinson said: “Yes, I am sorry that I did that. It was not the right policy and we should have stopped it.

“And our manifesto makes clear that that should be scrapped.”

She added: “I am sorry about that. It was one of the things that we did get wrong.

“We did spend five years in a coalition government where clearly we didn’t win every battle against the Conservatives.

“We fought many battles, and we did win many battles for more money for schools, for more money for the poorest pupils.

“There are many things that I am very proud of and where we made a difference, but of course there are things where we didn’t win those battles, and I am sorry about that.”

The gruelling interview underlines why Boris Johnson is avoiding a showdown with Neil, who took Jeremy Corbyn to task over Labour anti-Semitism last week. 

Swinson also used the interview to insist that neither Corbyn nor Johnson was “fit to be prime minister” and said the Lib Dems would push for a second Brexit referendum in a hung parliament.

Asked if the Lib Dems would prop up a Corbyn-led government, Swinson said: “I am not going to put Jeremy Corbyn into Number 10, but if a government of any colour puts down a Bill in Parliament to have a people’s vote, then we will support having a people’s vote to put a specific Brexit deal to the people with the option of remaining in the EU.”

Swinson added: “If Boris Johnson or Jeremy Corbyn don’t win a majority at this election then there is no guarantee that they are still going to be the ones that are leading their parties a week afterwards.

“So, Liberal Democrats will work to stop Brexit. We will support legislation that puts in place a people’s vote and we will work across parties.”

The election campaign has been tough for Swinson with plummeting personal poll ratings.

Asked why voters seemed to like her less the more they got to know her, Swinson said: “I don’t know the answer to that question.

“I have seen some polls that say something slightly differently to that. At the end of the day, I am going to stand for what I believe in. And there will be people who dislike that.”