Jeremy Corbyn has become Theresa May’s staunchest supporter. He feels with every fibre of his being that for a leader to be chucked out just because his or her own MPs regard him or her as unfit for high office would be a dark day for our nation, and especially for Corbyn.

Once she is gone, how long can he hold on? It is no surprise to find that Corbyn has formed the National Union of Leaden Leaders In Troubled Years, known for short as Nullity, with a membership of two.

At the very least, he wants her to stay in office until he can fight another general election against her.

The Leader of the Opposition made no attempt today to topple her with a knockout blow. He refrained from observing that she only remains in Downing Street because her own MPs cannot decide which of them should replace her.

Corbyn resorted to a joke. He suggested the Prime Minister could take “some tips from Jurgen Klopp on how to get a good result in Europe”.

May was ready for this. She replied that “when everyone says it’s all over, when your European opposition have got you beat, the clock’s ticking down, it’s time to concede defeat, actually we can still secure success if everyone comes together.”

Yes we can, if everyone comes together, but as Corbyn could have observed, while Liverpool secured their amazing victory last night by playing as a team, roared on by fans who believe in them, the Tories are not playing as a team, and their fans (if that is the word) are utterly demoralised.

Corbyn spared his fellow Nullity member by switching to the National Health Service, a good subject on which to electioneer, but one with no immediate bearing on Brexit.

Ian Blackford, the parliamentary leader of the Scots Nats, though eligible for membership of Nullity, has not been allowed to join, for Corbyn has decided to keep it as a closed shop.

Blackford made a bad start by congratulating the Duke and Duchess of Wessex on the birth of their baby. There was a lot of noise before he could change Wessex to Sussex.

The Prime Minister suggested he meant the Earl and Countess of Dumbarton, as they are known in Scotland. This struck some of us as coming a bit too close to dragging the happy couple into politics.

When Blackford at last managed to ask when the Commons is going to get another chance to vote on Brexit, May was unable to tell him, and fobbed him off with the tired old formula, “They want us to get on and deliver Brexit.”

Andrea Jenkyns (Con, Morley and Outwood) said the Prime Minister has tried her best to deliver Brexit but has failed, so it is time for her to “step aside and let someone new lead our party, our country and the negotiations”.

May retorted that “this is not an issue about me”, and added: “If it was an issue about me and how I vote we’d already have left the European Union”.

Like Corbyn, she confuses her personal righteousness with her right to carry on as leader.

The proper test for a Prime Minister is whether he or she can command a majority in the Commons. May can’t, which is why pretty much everyone on her own side has lost faith in her, and she has been reduced to appealing to her fellow Nullity for help.