Harrison got to the hotel less than ten minutes after the manager had visio’d him. Two men followed him in, one of them sauntering casually across to the desk and giving no sign of recognition.

Twenty yards away the squad car hummed a throbbing note as it generated the screen which would impenetrably surround the hotel until Harrison had finished.

The man at the desk said: “Room with a bath for two days.”

“Earth atmosphere. sir?” said the desk clerk.