"Oh," he laughs, waving one hand in the air. Only in Britain do experts denigrate their own specialism. "We’re the masters of intangibles and prediction. It all begins with traffic jams, if you can believe it. The city is tidal, and not just because of the river." Fingers flick towards it, fold up again. "People come to work in the morning, leave in the evening. There are crosscurrents from tourists—transport hubs. It’s complex. We manage the interactions. When you get stuck in the Blackwall Tunnel, that’s me having a very bad day. The end of the football season is always a complete—well, I won’t use the word I was going to use, I’ll let you fill it in. And in the end it’s not real. It’s perceptual. The weather forecast says one thing, the public mood says another, the economy is up or down, the news is good or bad. What fuzzy variables produce what decisions that result in a snarl-up at Hanger Lane? You have to understand that over the course of a year, bad traffic is massively expensive in terms of lost business, public health, unnecessary consumption of resources, and that’s before you factor in the soft variables like how traffic delays influence whether people consider they have had a positive overall experience doing business here. Our performance at Tidal Flow makes a genuine difference to the figures for the capital. So we’re a hotchpotch. Behavioural economics, mathematics, of course neuroscience. Self-organising criticality. They hate us at university departments, because everything we publish is interdisciplinary and doesn’t fit their models, but it’s evidence-based so they have to pay attention. Models are never quite good enough. The territory is always new."