‘Not forgetting your wheels,’ Charlie said, twirling as she got near his British racing-green Mini, with a Union Jack flag across the roof.

‘I do OK,’ Harry said humbly, unplugging the Mini. ‘And grub like this is a treat. I burn heaps of calories running, but rich food is terrible for my skin.’

Maker’s Yard was a two-minute drive on a road with speed humps that ran round Swallow Park’s manmade lakes. Charlie wowed as they passed an ultra-modern house with a white Ferrari on the driveway.

‘You’re good at making money,’ Charlie observed. ‘This is where you’ll end up.’

‘You’ll do OK with that big brain,’ Harry told her.

Maker’s Yard was an aluminium-sided building at the edge of Swallow Park. It was screened behind a fifteen-foot hedge, next to recycling bins and a garage that housed the little carts used by security patrols.

It took a while to find the unassuming entrance. The yard was the size of a basketball court. There was a whiff of burnt wood and motor oil. The décor was trendy industrial, with a bare concrete floor, stripped walls, particle-board benches and some pricey-looking machinery along the edge.

An elderly woman was gluing a vintage record player in one corner, but the main action centred on a pre-teen gang building little carts, covered with stick-on solar panels and powered by repurposed washing-machine motors.

‘Can I help you?’ their pink-haired, heavily pregnant teacher asked.

‘I messaged Steve,’ Harry told her. ‘We came to check this place out, and maybe for my friend here to join up.’

The punkish teacher explained that Steve had gone out to buy materials for another class later that afternoon. They waited on ancient comfy sofas in a lounge area. Besides the sofas, there were shelves of old technical manuals, a bright green coffee machine that hailed from the 1970s and some homemade cakes next to a donation jar.

Charlie laughed when she saw a motion-sensing camera rigged up to an old-fashioned police siren. She couldn’t figure out how it worked, but the flashing blue light was clearly designed to shame anyone who didn’t pay for their cake.

Moms of the kids doing the go-kart building sat on the sofas. There was also a beard-and-beer-gut in paint-spattered dungarees. He leaned on the back of a sofa, addressing the women like he was the world authority on everything.

‘All this talk about mutated virus, designer babies and this whole gene-editing show like it’ll be the end of days,’ he said in a booming Texas drawl. ‘But there’s always been scaremongering. It’s like this global warming. Been talking ’bout it for years, but I still ain’t seen Manhattan under twelve feet a water.’

Three moms nodded, while the fourth built blocks with a toddler sat on a sterile play mat.

‘Sure hope you’re right,’ one of them said.