Did Britain’s 20 years in Afghanistan end in triumph or disaster? We may feel we know the answer, but Boris Johnson was here to tell us that we are mistaken.

First, a word on Westminster, which was enjoying the first day of term on Monday, and the first day free of Covid restrictions. Or was it? In the chamber, and the corridors around it, the rules were straightforward: masks off for Tories, masks on for everyone else.

Policing the behaviour of others is a wearying pastime, but there’s something noteworthy about the Conservative party’s open contempt for the Conservative government’s rules. It’s like the US Congress serving cocktails on the floor of the Senate during Prohibition.

Almost no Tories were wearing facemasks. Matt Hancock, so recently the policeman of everyone else’s virus-spreading behaviour, wasn’t, as he sat crammed-in on the backbenches of a chamber that continues to be very much a crowded, poorly ventilated indoor space. Hancock had in fact been wearing a mask earlier in the day as he strolled around the building. Perhaps he just takes it off for the chamber. Vice-signalling, as it were.

There was some social distancing on the Tory benches. The gap between the Foreign Secretary, Dominic Raab, and the Defence Secretary, Ben Wallace, for instance, was definitely a metre, if not quite two.

On the opposition benches, Jeremy Corbyn was the most prominent mask-refuser, though he put one on when he realised he was in shot as Diane Abbott spoke. The former Labour leader’s attitude to Covid advice has been a noticeable throughout the last eighteen months. His brother, Piers, believes the vaccine “means injecting microchips into people’s bodies”. Corbyn has yet to offer a theory of who is behind it all. He may be saving it for the next Momentum conference.

The prime minister was the main attraction, with a statement on Britain’s retreat from Afghanistan, easily our most humiliating withdrawal from Kabul since 1842. But Johnson was there to tell us that it was, in many ways, a triumph.

“Our armed forces, diplomats and civil servants have completed the biggest and fastest emergency evacuation in recent history, overcoming every possible challenge in the most harrowing conditions, bringing 15,000 people to safety in the UK and helping 36 other countries to airlift their own nationals,” the prime minister explained, serious expression on face, serious haircut on head. “The whole House will join me in commending the courage and ingenuity of everyone involved in the Kabul airlift, one of the most spectacular operations in our country’s post-war military history.”

It was the Dunkirk argument: look at the wonderful effort getting the lads off the beach, don’t think too hard about why they were there.

France was safe from Nazi rule the whole time the British Expeditionary Force was there.

And please stop banging on about the ones who got left behind. Opposition MPs, and indeed Tories, kept asking about groups of Afghans now in mortal peril because they had worked with the British. Labour’s Helen Hayes said constituents trying to get help for family members were being passed between departments, and suggested – sensitive readers may wish to cover their eyes – that there was a lack of government coordination. Johnson roared with outrage.

“I must reject that in the strongest possible terms,” he fumed. This prime minister would brook no insult to our brave men and women in pinstripe. It felt slightly incongruous, but if the twice-divorced Johnson can persuade the Roman Catholic church that he’s never been married before, posing as the tribune of hard-working bureaucrats is straightforward.

In general, he tried very hard to imply that anyone questioning whether everything had gone as well as it could have done was personally insulting the military. Labour weren’t going to fall for that, with Keir Starmer proposing a medal for everyone involved in last month’s airlift. Everyone wanted to put on a flak jacket and say how much they loved the military. It was left to the Tory MP, Johnny Mercer, to say that Johnson still isn’t keeping the promises he made to veterans.

Has the Afghan adventure been a waste of time? Of course not, replied Johnson. “If anyone is still tempted to say that we have achieved nothing in that country in 20 years,” he said, “tell them that our armed forces and those of our allies enabled 3.6 million girls to go to school; tell them that this country and the western world were protected from al-Qaeda in Afghanistan throughout that period.” Also, France was safe from Nazi rule the whole time the British Expeditionary Force was there.