Grant sent him away to meet his milk-bar sweetie with a slight sense of relief. It was rather like having a mournful puppy around. He himself decided to postpone dinner for a little and go and see some of his Metropolitan friends.

He dropped into the Astwick Street Police Station and was greeted with the identical phrase that he had been listening to all the afternoon and evening: ‘Hullo, Inspector, what can we do for you?’

Grant said that they might tell him who was on the Britt Lane beat just now.

The man on the beat was P.C. Bithel, it seemed; and if the Inspector wanted to see him he was at this moment in the canteen having sausage-and-mash. His number was 30.

Grant found Number Thirty at a table by himself at the far end of the room. A French grammar was propped up in front of him. Looking at him, sitting there unaware, Grant thought how London policemen had changed in type in the short space of a quarter-century. He himself, he knew, was a departure from type; a fact that had been of great use to him on various occasions. P.C. Bithel was a dark, slight boy from County Down with a matt sallow skin and a kind reassuring drawl. Between the French grammar and the drawl, Grant felt that P.C. Bithel was headed for great things.

The boy began to get up when Grant had introduced himself, but Grant sat down and said: ‘There’s one small thing you might do for me. I’d like to know who cleans the windows of 5 Britt Lane. You might make a few inquiries when—’

‘Mr Lloyd’s place?’ the boy said. ‘Richards does them.’

Yes, indeed, and indeed P.C. Bithel had a future; he must keep his eye on P.C. Bithel.

‘How do you know that?’

‘I pass the time of day with him here and there on my beat. He stables his barrow and things in that mews further along Britt Lane.’