Jeremy Corbyn tried to look up his iPad during a live radio interview as he struggled to say how much his party's childcare policy would cost.

The Labour leader also flicked through his own manifesto in a bid to try to find the number during the chat with BBC Radio 4's Woman's Hour, according to presenter Emma Barnett.

She later told him that Labour had estimated that the cost would be £2.7bn a year.

Senior Labour figures have consistently struggled with figures related to their own policies during this election.

In a car crash radio with LBC shadow Home Secretary Diane Abbott said that her party's plans to recruit 10,000 policemen and women over a four-year period would cost about £300,000.

She later claimed the cost would be about £80 million.

Neither figure was correct.

Labour has unveiled plans for to roll out free childcare to all two-to-four-year-olds in England.

The party says that more than a million families south of the Border will benefit.

During the interview there were several awkward silences and at one point Mr Corbyn asked: "Can we come back to that in a moment?"

Pressed on the issue, he had earlier said: "I'll give you the figure in a moment."

Ms Barnett replied: "You don't know it. You're logging into your ipad here. You've announced a major policy and you don't know how much it will cost?"

Mr Corbyn replied: "Can I give you the exact figure in a moment?", adding: "All of our manifesto is fully costed and examined."

She continued: "You're holding your manifesto, you're flicking through it, you've got an ipad there, you've had a phone call while we're in here and you don't know how much it's going to cost."

Mr Corbyn said: "Can we come back to that in a moment?"

Ms Barnett said it was "quite troubling" Mr Corbyn did not know the cost, adding "It hardly inspires the voters."