We have known for some time that Dominic Cummings’ preferred action upon leaving a room was to pull the pin from an imaginary hand grenade and toss it behind him. Anyone who can’t imagine what this would look like wasn’t at a British primary school in the early 1980s, when War was the only game for boys who didn’t like football.

It is now clear that on his final day in Downing Street last November, things went rather further. The Sketch pictures Cummings creeping round the building, attaching imaginary explosives at key structural points and then carefully running an imaginary wire to the next location, like David Niven in The Guns Of Navarone, making sure it goes under the carpet and over the doorways, so that the Jerries (and Carrie) don’t spot it. 

Spotting a wallpaper catalogue, he hides an imaginary bomb underneath it. Another imaginary booby trap is laid to tempt any dogs that come after him, disguised as an imaginary rat. Finally, he moves slowly towards the famous black door, walking backwards in a crouch as he pays out the imaginary flex. He stealthily places the imaginary reel of cable into the box of possessions waiting for him, and then walks down the street, listening to the imaginary muffled rustle as the imaginary wire continues to feed out of the imaginary hole he made for it. When he finally gets to the end of the street, he carefully strips the imaginary wire with his imaginary combat knife, and wraps it around the imaginary contacts of an imaginary detonator. Then he lights an imaginary cigarette, and waits.

Last Friday, he pushed the imaginary plunger. And on Wednesday, Boris Johnson blew up.

He must have arrived in the chamber pretty close to exploding. Keir Starmer’s first question was about the “bodies piled in the street” line, asking whether the prime minister had said it. A simple “no” would have done the job, but Johnson launched into a tirade about how he hadn’t said it, and Starmer couldn’t prove he’d said it, but that if he had said it, he would have been entirely justified in saying it, although of course he hadn’t. 

The prime minister offered a reminder of why defence lawyers advise their clients to stay silent

Starmer looked unruffled, and reminded him that if he were found to have misled the Commons, he would be obliged to resign. This seems a rather optimistic take on Johnson’s approach to any honour-based system, but whatever. 

There then followed a set of exchanges in which Johnson grew ever angrier, while Starmer remained implacable. The Labour leader played the prosecutor, at times reminding the defendant of his rights, at times highlighting a point for the jury. The prime minister, meanwhile, offered a reminder of why defence lawyers advise their clients to stay silent.

Did Starmer want to know who had first paid for Johnson’s wallpaper? Well, said the prime minister, voters wanted to know about council tax in Labour areas. 

Starmer offered Johnson four options for where the money had come from – “I am making it easy for the Prime Minister, it is now multiple choice” – Johnson replied with a statistics on housebuilding. 

Had Lord Brownlow paid the money, Starmer asked. What about Tony Blair, Johnson answered. 

Had any laws been broken, the Labour leader asked. The public, the prime minister replied, were furious that he wasn’t asking about vaccines. 

This transparent swerving might have been more plausible if Johnson had adopted his usual approach, of making a game out of the whole thing. But he seemed genuinely furious. And the angrier he got, the calmer Starmer somehow seemed to grow, something that wound Johnson up even more. 

It was the howl of a bully complaining about being summoned before the headmaster

The Labour leader came to his final question. He began to list the principles that are supposed to govern public life, pausing after each one and looking at the prime minister, as though he were reading out a charge sheet. “Selflessness. Integrity. Objectivity. Accountability. Openness. Honesty.” Here Starmer paused for so long that he might have finished. The chamber was silent. “And leadership.”

Johnson, he said, was “Major Sleaze”. It’s not a great line, but neither is “Captain Hindsight,” which Tories treat as though it was handed to them on tablets of stone by Oscar Wilde himself. 

The prime minister blew up. Labour had attacked him for talking to James Dyson, but didn’t India now need ventilators, and weren’t there more nurses in the NHS? He was jabbing his finger at Starmer, shaking his head, waving his arms as he looked for support. He was shouting, the words tumbling out, barely making sense. More police on the street, the EU had voted for his Brexit deal, and what about freeports, and vaccines, and, to sum up, “Vote Conservative on May 6”. 

The Tory benches shouted “More!” which is what they’re obliged to shout on these occasions, but they can’t have meant it. It had been a horror show, a man who has spent years making a joke out of his lies suddenly complaining that he’s being asked to tell the truth. It was the howl of a bully complaining about being summoned before the headmaster. If anyone doubted that Johnson had something to hide at the start of the session, they can’t have doubted it at the end.

Some distance away, in his imaginary sniper’s nest, Dominic Cummings took his eye away from an imaginary telescopic sight, and quickly, professionally, imaginarily took apart his imaginary high-powered rifle. Blood coursing through his OODA loops, he slowed his imaginary heart rate, paused, picked up his imaginary spent shell casing and held it between forefinger and thumb. ‘Blob you’ he grunted.