SJ, a content designer, also from London, says even in a competitive environment she finds puzzling “peaceful. It centres me.” She and Dan are also competing in pairs – the mixed doubles of the championship, so to speak – when they will have 75 minutes to complete a 500-piecer. “Generally I start from the top down. She starts from the bottom up,” says Dan. Both concede SJ is faster, but, she says, Group B is “the most stacked with talent. Just remember that when people start clapping and finishing.”

Great. I meet nine-year-old Alma Belle Baharal, from Gibraltar, Spain’s national jigsaw champion (children’s category) for three years running, who also came 19th out of 400 in the adults’ category this year. Tomorrow she is competing for Britain in pairs.

She insists she’s not nervous: “It’s relaxing!” Then again, she has been puzzling since her mum Maya, 48, a teacher, bought her a wooden puzzle when she was six months old. “Try flipping the pieces over in under three minutes,” Alma advises. Yet it’s my stomach that’s flipping as I decline Steven’s offer of a slice of pizza – “some people find puzzling makes them hungry,” he says – and run to the toilet for a last-minute panic wee.

As soon as we start and I open the puzzle, my heart sinks. Unlike Group A’s Ravensburger puzzle, “Boathouses in Smogen, Sweden,” ours – “Sunset in Copenhagen” – has no sharp lines or bright colours. It is an interminable mass of faded sky, sea, people and buildings that I have no idea how to navigate. Can I complain?