“I understand you prepared and gave the camphor injection and prepared the anti-gas injection.”

“Yes. I didn’t put hyoscine in either if that’s what you’re thinking.”

“No doubt there will be some means of proving that,” said Alleyn smoothly. “I shall have the matter investigated, of course.”

“You’d better,” snorted Banks.

“Sir John prepared and gave the hyoscine.”

“Well, what if he did? Sir John Phillips wouldn’t poison his worst enemy in the theatre. Too much the little surgeon.”

“I’m glad you think so,” said Alleyn mildly.

Banks was silent.

“I hear you look upon the affair as a dispensation of Providence,” he added.

“I am an agnostic. I said ‘if.’”

“‘If’?”

“If I wasn’t, I would.”

“Oh,” said Alleyn. “It’s cryptic, but I get you. Can you tell me which members of the party were alone in the theatre before the operation?”

“No, I can’t.”

“Do try. Do you remember if you were?”

“No. Phillips was. Thoms was.”

“When?”

“Just before they washed up. We were in the anteroom. Phillips came in first and that little fool followed him.”

“Meaning Mr. Thoms?”

“I said so, didn’t I?”

“Are you going to hear Nicholas Kakaroff speak to-night?”

This was a shot in the dark. Kakaroff was to address a large meeting of Soviet sympathisers. The Yard would think it worth while to put in an amiable appearance. Nurse Banks threw up her chin and glared at him.

“I shall be proud to be there,” she said loudly.

“That’s the spirit!” cried Alleyn.

Inspired perhaps by fiery recollections of former meetings, Nurse Banks suddenly came out strong with a speech.

“You may stand there with a smile on your lips,” she stormed, “but you won’t smile for long. I know your type—the gentleman policeman—the latest development of the capitalist system. You’ve got where you are by influence while better men do bigger work for a slave’s pittance. You’ll go, and all others like you, when the Dawn breaks. You think I killed Derek O’Callaghan. I didn’t, but I’ll tell you this much—I should be proud—proud, do you hear, if I had.”

She reeled all this out with remarkable fluency, as though it was a preposterous recitation. Alleyn had a swift picture of her covering her friends’ suburban tea-parties with exquisite confusion. Small wonder the other nurses fought shy of her.