Is Jeremy Corbyn secretly trying to prop Theresa May up? For he gave no sign today of wanting to get rid of her. She has just carried out what this site has described as “The worst-handled reshuffle in recent history – perhaps ever”.

But how half-hearted Corbyn sounded as he accused her of being “too weak” to sack the Health Secretary, Jeremy Hunt. The hunt for Hunt was not sustained, and no sense was conveyed that the country would be better off if Corbyn were in charge.

The Leader of the Opposition claimed Hunt had insisted on going back on board ship, and concluded: “Under his captaincy the ship is indeed sinking.”

Were that image true, one would have to conclude that Hunt is a very gallant officer, who knows where his duty lies. But Corbyn failed to make one believe even for a millisecond that the NHS, for all its winter difficulties, is actually going down.

Nor, in fairness, should one pretend May conveyed any real sense that the Government is prospering. She lacks the fire and eloquence to raise Tory hearts.

But she does have the doggedness to keep trudging forwards towards Brexit. That task provides her with the vital function of giving expression to the wishes of the British people.

And Corbyn did not dare ask her about that, for he knows how deeply divided his own MPs are from Labour voters about Brexit.

If Corbyn were to be replaced by a more inspiring Labour leader, May would come under irresistible pressure to step down.

If May were to be replaced by a more inspiring Conservative leader, Corbyn would come under irresistible pressure to step down.

So it is not too fanciful to regard them as locked in an unacknowledged pact. They have by accident attained a fragile balance, in which each of them compensates for the other’s weaknesses.

According to a French proverb, only provisional arrangements last. We’ll see how long this one does.