The bill arrives. Everybody goes quiet.

There is a specific silence that falls over a British table when the card machine appears. Someone has had three cocktails. Someone has had tap water. Someone is doing arithmetic behind their eyes and pretending not to.

Every friendship group solves this differently, and every solution is a small constitution: what we owe each other, rounded to the nearest pound.

The equal-split camp says itemisers are cheap. The itemisers say equal-splitters are freeloaders with expensive taste. Both privately believe they are subsidising the other.

And then there is the darker move: the friend who 'forgets' their wallet. Once is misfortune. Twice is a policy.