LEEDS, England — The problem, for Peter Critchley, is that the phone just keeps ringing. At least 30 calls a day, every day. Then there is the online backlog: He has 100 more requests on his website to wade through every evening. He has already added some 600 new customers, and more just keep coming.

Suddenly, it seems, everyone wants a milkman.

The surge has been going on for a week or so, Mr. Critchley said. As the British government’s measures to slow the coronavirus’s spread have grown incrementally tighter, as towns and cities have fallen quiet, as shops have closed and communities — mostly — started to follow officials’ advice to stay at home, more and more people have turned to Mr. Critchley, and others like him.

It is one less reason to venture outside, one way of avoiding snaking queues and empty shelves at supermarkets, at least one essential that can be guaranteed.