The question of Brexit has been “vulgarised by frequent handling”, to borrow an expression used in a different context by Sir George Otto Trevelyan in his marvellously entertaining work The Early History of Charles James Fox.

Nobody could call today’s PMQs marvellously entertaining. The two main actors, the Prime Minister and the Leader of the Opposition, see no profit in trying to amuse us.

They prefer to use the same material over and over again, as if mere repetition makes it more convincing. Theresa May reproached Jeremy Corbyn for refusing to take part in talks on Brexit: “Why won’t he come and meet me and talk about it?”

Corbyn accused her and her colleagues of having an open door, but “apparently the minds inside it are completely closed” – a charge already heard on Monday from Hilary Benn.

May remarked that Corbyn, who enquired whether she ruled out joining a Customs Union, did not understand what he is talking about: “I don’t think he knows what those phrases mean.” This is probably true. Her command of detail sounds a hundred times better than his.

But for much of the time, she uses that command of detail to avoid giving anything away. Bland generalities which cannot offend anyone are more her style.

As a defensive screen, this is more than enough to keep Corbyn at bay. If she were a batswoman, one would say she prodded and blocked and looked in no danger of losing her wicket, but also that she scored very few runs and by the end of play had driven many spectators out of the ground.

To look so steady at a time of such stress is an achievement. She used to put on the same kind of performance when she was running the Home Office.

The trouble is that she does nothing to raise her backbenchers’ spirits. But then Corbyn does nothing to raise his MPs’ spirits. In that respect, they are well-matched, and have achieved a kind of balance.