He tapped on the window and the taxi stopped. The two detectives got out. Their breath hung mistily on the frosty air. Alleyn spoke for a moment to the driver and then looked inside.

“Thank you so much for your help, both of you,” he said.

“I say, Alleyn, I hope you don’t think we’ve made awful mugs of ourselves?” said Nigel lugubriously.

Alleyn thought for a moment.

“It was a very spirited effort, I consider,” he said at last.

“We shall have to get you both in the Force, sir,” added Fox. His matter-of-fact voice sounded oddly remote out there in the cold.

“Ah, Inspector Fox,” said Nigel suspiciously, “I’ve heard you say that before.”

“Good night, Comrade Angela,” said Alleyn, “sleep well.”

“Good night, inspector; I don’t grudge you your joke.”

“Bless you,” answered Alleyn gently and slammed the door.

The taxi drove off. Farther along the Embankment men were hosing down the street surface. A great fan of water curved out and made all the sound there was except for the siren and the distant toot of the taxi. The two men stared at one another.

“I wonder just how much harm they’ve done,” said Alleyn.

“None at all, sir, I should say.”

“I hope you’re right. My fault if they have. Come on, let’s have a smoke.”

In Alleyn’s room they lit their pipes. Alleyn wrote at his desk for some time. Fox stared gravely at the opposite wall.

They looked a queer couple with their dreadful clothes, grimy faces and blackened hands.

“She seems a very nice young lady,” Fox said presently. “Is she Mr. Bathgate’s fiancée, sir, if I may ask?”

“She is.”

“A very pleasant young couple.”

Alleyn looked at him affectionately.

“You’re a quaint old bag of nonsense.” He laid down his pen. “I don’t think, really, I took too big a risk with them. The little man was nowhere near them. You recognised him, of course?”

“Oh, yes—from the inquest. I didn’t see who it was till he passed us in the doorway, but I’d noticed him earlier in the evening. He had his back towards us.”

“Yes. I saw him, too. His clothes were good enough to shine out in that assembly. No attempt made to dress down to comrade level.”

“No,” said Fox. “Funny—that.”

“It’s altogether very rum. Passing strange. He walked straight past Sage and Nurse Banks. None of them batted an eyelash.”

“That’s so. If they are in collusion, it might be deliberate.”

“You know, Fox, I can’t think this Communist stuff is at the root of it. They’re a bogus lot, holding their little meetings, printing little pamphlets, making their spot of trouble. A nuisance from our point of view, but not the stuff that assassins are made of. Of course, given one fanatic—” He stopped and shook his head.