“Six thousand new members in a day!” crows our Brexit Party seminar leader, Paul. “The Tories would kill for that. When I was watching it, it was one every few seconds – each giving us £25 a time to become a registered supporter.”

That was last Friday – 6th September. It’s now Tuesday. British politics is warping and folding by the hour, and nothing is more of a collapsible waveform than the Brexit Party. If Boris wins: they are crushed. If Boris shanks it: they eat his brains.

Had the recent European election results been replicated at a general election under our electoral system, those results would have magnified out to the Brexit Party winning a swingeing majority of 240 seats.

But that’s precisely the point – general elections are very different to Euro elections. They’re fundamentally local, they hugely favour the incumbent duopoly, and they require very different tactics.

In any campaign, there are two spheres. There’s the air war – who’s leading the news at ten, what’s on the front page of the Mail, the pissing contest of the leaders’ debates. Then there’s your ground game: door-knocking, basically.

It is to that lost art that this seminar is dedicated. We’re on a golf course, ten minutes outside the joyless splodge of Walsall, north of Birmingham, in a conference room still rigged with the chiffon drapes and chintz candelabras of the weekend wedding trade.

Here, about 70 greying souls – uniform of dinner jacket, jeans and brogues obligatoire – are being drilled in the dark arts of street-by-street canvassing.

Today, the Brexit Party are lifting the lid on their secret weapon. “When I was organising for the Conservatives in the Greater London Authority… well, vipers’ nest hardly covers it,” grins our next speaker of the day, party marketing boss Toby Vintcent, to laughter. “I became convinced that the structure was holding us back. Both Labour and the Conservatives have effectively 19th century party structures.”

They want to be the opposite. Nigel Farage has built a pair of parentheses where a party should go. It’s no secret that by the end of his time, Nigel had grown to hate UKIP – with its turgid internal democracy, and endless personal feuds – and was glad enough to bin it. The Brexit Party is meant to be his blue skies response to the question: "If you were going to build a party for the 21st century, how would you do it?"

First, you wouldn’t have “members” who can “vote”, because that slows down the decision-making chain. Instead, you’d have “registered supporters” who “help out”, without expectation. The executive hand-picks the candidates – there are no Tory or Labour-style de-selection tussles. The Brexit Party can react rapidly, because it’s run more like a corporation than a local authority. CEO Farage points to things, CFO Richard Tice finds the money, and stuff happens, fast.

Second, you’d harness the intersection of the crowd and the cloud. And here’s where the Brexit Party again believe that they are outmanoeuvring the ancien regime. They’ve paid a lot of money – “really a lot of money”, Paul boasts, “like they could have chartered their own plane here…” – to buy the best ground game software out there: Pericles. So much money that the two American political consultants who sold it to them have turned up in person to unpack it.

“If it’s a firm ‘no’, just record that and just move on,” one of them intones. “Remember that your time is limited. We only want the potential converts. In fact, it’s one of the tricks of the trade by the opposition, to keep you talking on the doorstep…”

In 2019, the big three parties still rely on paper returns. Their canvassers go out. Ding-dong. Gently probe your voting intentions. Write your answers down on a sheet of paper, and walk back to an office somewhere where some sad lackey enters each manually onto a computer.

The endgame of the ground game comes on polling day. Party tellers stand outside polling stations and cross you off their list. If you haven’t turned up yet, they might send canvassers back to knock on your door – to give you a lift if necessary.

While the big three are still so arthritic that they’re still running those numbers back to an office, Pericles can crunch all those numbers in real-time. And map it in real time too, building a local map in which each missing voter is a blue flashing dot, that canvassers can head towards. Then – if they suddenly turn up at the polls just as you’re about to knock on the door – the blue light goes dark.

With enough bodies to man it, this gifts you a real-time, endlessly-rotatable data set that can make a difference of hundreds of votes. And in our present clownworld where every British marginal is about to go from a classic two-way split into a four-way tussle, a few hundred votes could easily be all there is in it.

“Don’t forget, I was in UKIP once,” Paul tells them. “In 2015. We came second in 150 seats. Four million votes – and not one new seat.”

It’s the spectre they fear most, a nightmare scenario they’re determined not to repeat. On cue, Toby pulls up a list of the Brexit Party’s top hundred target seats. “We can track, at a glance, how well voter pledges are going in each constituency.”

“And in that sense, I’m afraid Big Brother is watching,” Toby trills. “We’ll be monitoring your success or failure closely. But of course, that means we’ll be able to throw more resources into your area – more canvassers and the like.”

It’s the plug-in-n-play nature of Pericles that’s the killer app. When you’ve got a large voluntary workforce of recently-recruited pensioners, the key to agility isn’t sophistication: it’s idiot-proofing (though it may have met its match in the paunchy chap, head cocked back, squinting down his bifocals into his clamshell Motorola).