In the theatre of politics, sounding confident, robust, sure of your ground and in command of your brief are all valuable qualities, and so is the ability to make the most of what may be a rather thin case.

Boris Johnson today showed all these qualities. Part of the charm of the Commons is the rapidity with which things can go wrong, the suddenness with the vulnerability of a dominant leader can be exposed.

Sir Keir Starmer could not today bring about such a reversal of fortune. He wanted to play things both ways: to show that Labour was standing shoulder to shoulder with the Government in defence of Ukraine against Russian invasion, while at the same time suggesting the Government’s response had been pitifully inadequate, so did not deserve support.

Johnson too was playing a double game. “I am grateful for the broad support we have had today,” he said at the end of Sir Keir’s questions, but he also wished to demonstrate that Labour was an unreliable partner.

So in his last reply at PMQs, Johnson said he had heard someone on the Opposition benches call the Government’s response “weak”. The Prime Minister retorted that on the contrary “it’s going to be very strong”, and added that “something that would be strong, Mr Speaker, will be to take the Whip away from the 14 members of the Labour Party who say that the aggressor in Ukraine is NATO.”

No chance for anyone on the Labour benches to reply to that attack. It was all over, and Johnson had much preferred talking about Ukraine to discussing, or refusing to discuss, what parties he had attended.

Prosecco and cake had at least temporarily been removed from the Commons menu. Putin had done Johnson a favour by forcing a more serious subject on everyone.

Whether in Ukraine or in the United Kingdom, the Prime Minister loves defending sovereignty, democracy and freedom of speech. Here were echoes of Periclean Athens. No need to say this is also what Brexit was about: anyone of any intelligence would get that.

A number of backbenchers asked verbose questions which wasted the House’s time, gave Johnson longer to think and made any evasiveness in his replies less embarrassing.

The Speaker, Sir Lindsay Hoyle, did what he could to shut these dim-witted wafflers up.