PMQs: David Cameron left on a high but the comedown is coming

As the heir to Blair will soon find out, never is a great communicator more exposed than when the communicating comes to an end

David Cameron speaks during Prime Minister's Questions in the House of Commons (Reuters)

That the nation has run Coyote-like off the cliff edge but is still waiting for the fall has been the most commonly repeated metaphor of these mad times.

But at the end of three long weeks of running on air, Coyote Cameron achieved the impossible. His final Prime Minister’s Questions over, he cleared the ravine and landed safely on the other side. But in the coming months and years this self-styled heir to Blair will, with frightening de ja vu, be forced to look on as his reputation nosedives to its doom.

Cameron, in his final hour, was a class act. How long he has sat on “an email from Judith”, sent in September, foreseeing Jeremy Corbyn’s woes as Tom Watson machinates around him. To parody your opponent as you demolish them is rather brilliant, even if it has been close to a year in pre-preparation. He had brought a picture with him to scotch rumours that he was no fan of Larry the Number 10 cat – feline lovingly perched in the lap of power.

He compared Mr Corbyn to the Black Knight in Monty Python’s Holy Grail, but not even King Arthur was that mockingly cruel as he severed all four of his hapless opponent's limbs. And certainly not when, as is customary, it would fall to Labour's Black Knight to say something nice in return. In the end, Mr Corbyn passed on his good wishes to the Cameron family, even to Cameron’s mum, for “the advice on suits and ties and songs” that she had herself never actually given.

To depart from the nation's higest office via a semi-congratulatory session at the despatch box is by no means customary, so the comparisons with Blair are fair. When a politician’s greatest weapon is communication, never will they be more exposed than when the communicating stops. When you are no longer around to justify your actions, even as their consequences continue.

The most moving moment of Blair’s departure nine years ago came from the lower benches, where the smaller opposition parties sit. The Reverend Ian Paisley, 81 years of age, paid tribute to the historic peace that had been brokered in that corner of the kingdom.

Nine years on, from those same benches rose Angus Robertson of the SNP, to forewarn that the Scottish National Party would not be applauding Cameron: “The Prime Minister's legacy will undoubtedly be that he has taken us to the brink of being taken out of the European Union.” The legacy that comes with it, will be an ever more committed nationalist movement, determined to break the Union.

“I will be willing all of you on,” Cameron said as he departed, reserving his final tributes for Parliament itself. “People come here with huge passion for the issues they care about. They come here with great love for the constituencies that they represent. I will be willing on this place.”

A noble sentiment, that will do for the moment. But in the coming years, he will be remembered solely for his decision to subvert it.

Parliament applauded as he left. The Conservatives up on their feet, a small handful of Labour too. Even Paul Flynn, an 81-year-old anarcho-syndicalist suddenly having a taste of life on Labour's front bench, the oldest parliamentarian to do so since Gladstone, rose to his feet. In the far corner, Boris Johnson had snuck in for this very final scene.

But it wasn’t parliament that has finished Cameron off. It was the people – and finished themselves off too.

How often it has been said in the past few weeks that politics is brutal? But it has a brutal sense of humour to go with it. As her Majesty spent a second sunny Wednesday afternoon waiting for the crash to earth of a brilliant young high-flyer who never noticed that his wings were made of wax, what should be the subject of debate in the Commons this afternoon? The Report of the Iraq Inquiry: Day 1.