Jeremy Corbyn was unable to put a cost on Labour’s plan for free childcare for 1.3m youngsters during an interview with BBC Radio 4’s Woman’s Hour.

“It will cost… it will obviously cost a lot to do so, we accept that,” he said, when quizzed about the figures by Emma Barnett.

The stumble came as the Labour leader and Theresa May resumed election campaigning following a live TV debate.

Mrs May will argue she is the only one who can offer “strong leadership”.

In other election news:

The Scottish National Party launched its manifesto

Theresa May claimed that on Brexit negotiations: “I am ready to go. Jeremy Corbyn is not”

Green Party co-leader Caroline Lucas said the low profile of environmental issues in the campaign was “scandalous”

Viewing figures suggest 2.9m turned in to watch Jeremy Corbyn and Theresa May’s TV special on Monday

It was during his interview with Woman’s Hour that Mr Corbyn had to be told by interviewer Emma Barnett the cost of his party’s manifesto proposal to extend 30 hours a week of free childcare to all two-year-olds – a policy which is part of Labour’s plans for a National Education Service.

BBC political editor Laura Kuenssberg said that Mr Corbyn’s performances had been getting better during the election campaign, soit was “astonishing he was not across the figures for the childcare policy” his party was campaigning on today.