Pounding across the political landscape, terrorising enemies, leaving chaos in his wake, Boris Johnson has for years resembled some kind of gigantic shaggy ape. You might have wondered about the wisdom of bringing him back from Skull Island and putting him on display in Westminster, but you had to admit it was an impressive sight.

Handlers learned he could be rendered docile by the sight of a woman, ideally one reading chunks of Shakespeare. And if you wanted him to go and beat somebody into a pulp, all you really had to do was point him in the right direction. He was, in particular, impervious to things that slowed or even stopped lesser politicians, such as reality. Over the decades, Tory and Labour MPs have both flown at him in their biplanes, fixed him in their sights, only to discover that facts simply bounce off him, and that he could swat them aside.

Now, as he begins to lose his grip, the magnificent beast still behaves as he did when the puny humans couldn’t hurt him, but it is becoming clear that they can.

Britain is once again world-beating, though this time it’s in Covid transmission

He looked a mess at Prime Minister’s Questions. Three months ago, at the start of the term, he was bullish, glad to finally face Keir Starmer in a full Commons chamber, delighting the Tory ranks behind him as he taunted the Labour leader. His hair was neat, his suit sharp, and his MPs hung on his every word. On Wednesday, we saw the effects of captivity. He was dishevelled, heavier, paler. The cheers on his side were dutiful, rather than spontaneous.

On the front bench next to him his Cabinet looked serious. They were masked, a distinct contrast from September, when they were merely telling everyone else to wear masks. Next to him was Liz Truss, the Foreign Secretary, who had that morning released her official Christmas portrait, presumably on the grounds that if she stops releasing vanity shots, the virus will have won. The general assumption is that she wants to take over, but, if she did, it’s not clear what she would do differently.

Later, we would get a sense of the problems facing this prime minister and facing any successor. At a frankly grim press conference, Chris Whitty announced that Britain was once again world-beating, though this time it’s in Covid transmission. New cases are at the point where the government is going to have to start adjusting the scale on its graphs to fit them in. But Johnson is constrained by his backbenchers, who hope that if they ignore Covid, it will go away.

The result was a classic Johnsonian compromise. “We’re not cancelling people’s parties or their ability to mix,” the prime minister said. “What we are saying is, think carefully before you go.” So you can still hold a Christmas party, you just shouldn’t attend any. Pro-having Christmas cake and pro-eating it, just so long as you’re alone when you do it. Or, more pertinently, you can still open your pub, but the government is telling everyone to stay home. Perhaps the Covid Recovery Group of Tory MPs will take that as a win.

It’s hard to debate with someone who gets their facts from a parallel universe

At PMQs, Starmer danced round Johnson. It’s not so much that he’s got better as that the prime minister has got so much worse. The Johnson approach is still the same: whatever the question, the answer is the vaccine rollout. If Labour criticise him, they’re “playing politics”. And if someone raises something he doesn’t like, he just denies it.

Starmer opened by asking Johnson what he thought of the 101 Tory MPs who had voted against restrictions the previous evening. “The House voted through Plan B with Conservative votes,” Johnson insisted. It was Labour who had “wibble wobbled”, he said. “That is the reality.”

Once, this stuff would have had Labour tearing their hair out: it’s very hard to debate with someone who seems to be getting all of their facts from a parallel universe. Now they just laughed. Once Tory MPs would have cheered as the mighty Boris roared his way through the jungle, the earth shaking as he passed. But they have been watching in the last few weeks, and they have their doubts.

Starmer reminded Johnson that he had needed Labour’s help with the vote. “Not true!” Johnson shouted. Starmer was delighted. “He is so socially distanced from the truth that he thinks that is not true!” He read out the things Tory MPs had said about their leader, and taunted him as “too weak to lead”.

Tom Tugendhat asked if the Foreign Office was planning 10 per cent staff cuts. Johnson floundered and then told him it was “fake news”. Except an all-staff email later in the day showed it wasn’t. At his press conference he insisted once again that he always follows all the rules he sets for others, but we’ve all seen the pictures that show he doesn’t.

How will the story end? What will bring down this apex predator? A lot of us thought that booty calls would kill the beast, but it looks like being reality that will finally do the job.