The cortège reached Scotland Yard without mishap; the gates at both ends were closed, and the prisoner was rushed into the building.

Balder, Elk’s clerk, and a detective-sergeant, took charge of the man, who was now white and shaking, and he was put into a small room adjoining Elk’s office, a room the windows of which were heavily barred (it had been used for the safe holding of spies during the war). Two men were put on duty outside the door, and the discontented Balder reported.

“We’ve put that fellow in the waiting-room, Mr. Elk.”

“Did he say anything?” asked Dick, who had arrived for the interrogation.

“No, sir—except to ask if the window could be shut. I shut it.”

“Bring the prisoner,” said Elk.

They waited a while, heard the clash of keys, and then an excited buzz of talk. Then Balder rushed in.

“He’s ill . . . fainted or something,” he gasped, and Elk sprang past him, along the corridor into the guard-room.

Mills half sat, half lay, against the wall. His eyes were closed, his face was ashen.

Dick bent over the prisoner and laid him flat on the ground. Then he stooped and smelt.