Jeremy Corbyn's car-crash 'Woman's Hour' interview has undone all of his good campaign work

Just when Jeremy Corbyn was unmistakably in the election game after an impressive showing in last night’s TV non-debate, he has made a mess of it the morning after.

His interview on BBC Radio 4’s Woman’s Hour was embarrassing. He started badly when he could not say how much Labour’s plans to expand free childcare would cost. “A lot” was the best he could do. Wisely, he didn’t do a Diane Abbott and make up a figure. But there was an excruciatingly long pause while, his interviewer Emma Barnett informed us, he consulted his iPad and was sent a message by his aides. Although he just about managed to remain in what he calls his “Monsieur Zen” mode and did not turn on his inquisitor, he never really recovered his poise.

In the end, Barnett had to tell him the costings of his own policy. She quoted Angela Rayner, the shadow Education Secretary, who had outlined them on Radio 4 a few hours earlier. Corbyn should have had them at the front of his mind, or at least on a bit of paper because childcare was Labour’s chosen issue of the day (as it tried to play on its home ground of public services rather than security or Brexit).

Abbott’s disastrous LBC interview on police numbers, when she didn’t know how much Labour’s extra 10,000 officers would cost, should have been a salutary warning to Corbyn.

His minders should also have told him about an important rule of politics: it’s the soft interviewers that get you. In 1987, during an election when the Tories had a similar wobble to Team May’s one now, Neil Kinnock relaxed on David Frost’s Sunday morning sofa and was tripped up when Frost asked what a unilateralist Labour government would do if the Soviet Union invaded. Kinnock muttered about resistance to make an occupation untenable. The Tories rushed out a memorable poster, “Labour’s Policy On Arms”, showing a British soldier’s arms raised in surrender. (The wobble was short-lived and Margaret Thatcher won a majority of 102).

With Corbyn’s rising personal ratings among women largely responsible for Labour narrowing the Tories’ opinion poll lead, perhaps he was expecting an easy ride today. Certainly an easier one than he got from Jeremy Paxman in last night’s Channel 4/Sky News programme, in which Theresa May appeared to get a less sympathetic response from the studio audience than the Labour leader. He was very comfortable in his own skin, although a little wobbly when it came to defence matters. He was certainly more confident than May.

That was then; now it will be forgotten. His critics, inside and outside his party, will seize on today’s “car-crash interview”. It will allow the Tories to play the economic competence card against Corbyn, which strangely has been largely absent from this election, perhaps because of Brexit and the Manchester tragedy turning the spotlight on to security.

The Tories will be happy to have another line of attack. They will be able to say, not only that Labour’s sums do “not add up” (which got a frosty audience reaction when May said it last night) but also that Corbyn doesn’t even know what his sums are. Does it matter? Yes; no party has won an election in modern times when it has been behind on both best leader and economic competence.

Corbyn’s Woman’s Hour moment will become his equivalent of May’s incredible “nothing has changed” statement to journalists a week earlier, when she ludicrously denied her screeching U-turn on social care was just that. To be fair to Corbyn, May’s disaster movie was even worse because the decision to omit a cap on an individual’s lifetime care bills from the Tory manifesto was an unforced error. She compounded it by making an ungracious volte-face; instead of admitting a mistake, which voters might have given her some credit for, she was in denial about it.

Unfortunately for Corbyn, he won’t get any credit for making a slightly worse mistake than May. His one will be magnified by a largely hostile media which was grudgingly admitting he has defied their low expectations by fighting a good campaign.