Would you believe it? The European Research Group had significantly overestimated the number of people attending the launch of its new paper – why the UK should tell the EU to sod off: part 183 – and there were a few dozen empty seats by the time the event got under way at a converted church in Westminster. Perhaps a few of the invitation letters had gone astray. Or some of those who promised to attend just hadn’t shown up.

At a previous ERG event to launch an earlier paper – why the UK should tell the EU to sod off: part 156 – the Conservative MP Steve Baker declared himself to be a “numbers man”. As in, making up the numbers. In both senses. Ever since the former junior Brexit secretary was promoted to well above his pay grade as Jacob Rees-Mogg’s second-in-command, the ERG has struggled with basic maths.

For several months, the group had claimed it was only one or two letters short of the 48 needed to trigger a vote of confidence in the prime minister. So when Rees-Mogg announced that he too had sent his letter to the chairman of the 1922 Committee, Baker quickly predicted the 48 threshold would be reached within a day or so. However, it’s turned out there have been far fewer letters sent than had been promised. More imaginary numbers.

Quite what has happened to the other letters is unexplained. Given that many members of the ERG aren’t the brightest, it’s possible that some Tory MPs either forgot to put on a stamp on their letters, sent them to the wrong address, misspelled Brady as Brodie, or posted them by mistake into a rubbish bin. But if even Andrea Jenkyns, the ERG idiot’s idiot (a title bitterly contested by Andrew Bridgen), can manage the basics of letter writing then it’s safe to assume a group of Tory rebels fuelled largely by fantasy have unsurprisingly turned out to be fantasists.

Either way, the ERG has seemingly managed the impossible. In less than a week, they have made Theresa May appear vaguely plausible while relegating themselves to an embarrassing, long-past-its-best, music hall act. With Rees-Mogg as Archie Rice. In a straight fight between the ERG and Dad’s Army, Captain Mainwaring would come out on top every time. Tuesday’s event had all the feel of the final hurrah before the knacker’s yard.

Behind the stage was a placard with the words “Global Britain”. Global Britain turned out to be seven old, white men waiting for the golf club bar to open. Only the presence of Rees-Mogg brought the average age below 65 and he was feeling every one of his 49 years. Even he never thought he’d sink this low. Whatever would Nanny think?

Peter Lilley, a former trade secretary, got things under way as if he were auditioning for Dragon’s Den: he had virtually founded the World Trade Organization single-handedly; he was certain everyone was overexaggerating the problems of cross-border trade, as he had once brought a cheese from his second home in France back to the UK without being stopped; no one should worry about Kent becoming a car park as illegal immigrants had already turned it into one; and he’d never come across a trade deal he couldn’t negotiate in 10 minutes. Baker perked up at that. Ten minutes probably really meant five. Nothing escaped the numbers man.

The next three nonentity guests had little more to say, other than that they hadn’t read the paper but were sure they probably agreed with it. Sir David Ord – me neither – even managed to do this while appearing to be asleep. The rest of us should have been so lucky. It was left to a dishevelled David Davis to wrap things up. “I’m overawed to be in such distinguished company,” he began. He really needn’t have been. He was perfectly matched, with the stupidity bar set comfortably low.

Much to the panel’s disappointment, no one had any questions to ask about Global Britain. Mainly because it was all a rehash of what the ERG had put out several times before and been comprehensively dismissed on every occasion. Instead, everyone wanted to know if the 48 letters were ever going to materialise. Along with the more existential one of why an organisation should have gone to such lengths to prove its lack of credibility. So instead, Lilley recited something from the bible.

Come the end, a scrum rapidly surrounded Rees-Mogg, who did his best to persuade reporters that everything was going totally to plan. Apart from the bits that weren’t. The madness becomes ever madder. Even Labour organises better coups than this. Davis tried to use the fracas to escape the scene unnoticed before anyone could ask him if he had written a letter, only to find he had left his briefcase behind a pillar and had to fight his way back in to get it. The end of the end of the pier show.