I’m sticking my neck out here: I’m guessing that telling the supreme court in advance that you might just ignore its decision if you lose and go ahead and prorogue parliament a second time isn’t necessarily the best way of endearing yourself to the 11 judges. Shove your verdict where the sun don’t shine. Whatevs. But I’m not the prime minister.

Spare a thought then for Lord Keen, who was tasked with summing up for the government’s appeal against the Scottish court’s decision that it had acted unlawfully, when his client had gone rogue. These haven’t been a great three days for Keen. Ones he will be keen to erase from his memory. Admittedly Boris Johnson had dealt him a rubbish hand, but he still hasn’t played it that well.

On the first day of the hearing he had appeared almost comatose as he mumbled and meandered through his opening speech. This time he was rather better prepared. At lunch, one of his juniors had injected a massive shot of adrenaline directly into his heart to at least render him awake. Total coherence was still tantalisingly out of reach. Perhaps it was beyond anyone in his position.

Keen’s basic point was that the court should try not to worry its pretty little head about anything. The difference between dissolution and prorogation was more apparent than real and justiciability was not worthy of the judges’ consideration. Whether the suspension of parliament had been taken for legitimate or illegitimate reasons was also neither here nor there. In any case, who could doubt that the Incredible Sulk was a man of the highest integrity? Boris had always promised to lie and he had been as good as his word. So their lords and ladies should just take time out and put their feet up over the weekend rather than sweat the small stuff.

Not surprisingly, the judges weren’t overly impressed by Keen’s assertion that the documents were both straightforward and could also be read in a variety of ways, and pressed him to reveal what remedies the government had in mind if the decision went against it. Here Keen rather fell apart. He was used to dealing with honest criminals. People who at least knew the difference between right and wrong.

Now he was in a looking-glass world of narcissists and sociopaths. Politicians and advisers who could literally not be trusted to dress themselves in the morning. At this point, Keen started to worry if he would even get paid. Why did he always get the shit jobs? Er... Um... It might be tricky for the Queen and it wouldn’t leave so much time to write a Queen’s speech that hadn’t even been started, was the best he could come up with. He sat down, both crushed and relieved that his ordeal was over.

Except it wasn’t, as Keen was about to be shown up yet again by Lord Pannick, who delivered a closing speech that was even more devastating and forensic than his opening one. Piece by piece, he disassembled Keen’s argument. First on the facts. If the Sulk had really just intended to deliver a Queen’s speech on 14 October rather than stop parliament sitting, he could have prorogued on 7 October. Then it would have been up to the Commons to decide whether it wanted to go into recess for conference season. The constitution demanded the executive be subservient to the legislature.

Pannick even observed that one of the bills Keen – the poor, poor love – had been working so hard on in the Lords would now fall because of the prorogation. Keen looked as if he wanted to throw up. His own failures he could just about live with. Being patted on the head by his opposite number was an insult too far. Keen, though, was just collateral damage in Pannick’s drive-by shooting. Having left Keen to exsanguinate, Pannick took aim at James Eadie’s arguments on the law itself. The back of Eadie’s neck turned a bright crimson. He was so busted. Definitely a man you would want to play poker against.

All of which rather overshadowed a morning that had been notable for Michael Fordham using his encyclopaedic knowledge of case law to argue against the government’s position on behalf of Wales. He was heard without a single interruption. Largely, one assumed, because the judges were worried he knew the law better than them.

Next up had been Edward Garnier speaking for John Major. We’re beyond the world of satire when a former Tory prime minister can accuse the present one of being less trustworthy than a dodgy estate agent. An allegation that seemed rather harsh on dodgy estate agents. The constitution might be based on the assumption of a conscientious prime minister, Garnier said, but the judges should be aware they were dealing with a reckless one.

Come the end, Pannick tried to talk through the options open to the court if it chose to find the government had acted unlawfully. Lady Hale, the court president, agreed it wasn’t easy and promised to try to return with a decision early next week. Dominic Cummings had always promised to ruin the Labour party conference. Now there was a distinct possibility that parliament could be sitting for PMQs at the very time Jeremy Corbyn was due to give his leader’s speech. Classic Dom.