Visiting New York City for the first time, I spent a day at the Metropolitan Museum of Art with my sister. We were sitting on a bench resting our tired legs late in the day when a guard approached us.

"It wasn't made as a bench," Flynn said. "But I intentionally built it at that height so people could sit on it if they wanted to." You might give it the sit-down test if you pass by the site.

A 'really good day', he says, is worth £100-£150. His companion on the bench, Harvey, laments being too young to cash in on the action. "Covid put the company I work for completely out of business.