Thomson drew the thin sheet of paper from its envelope and swept a space for himself at the corner of the table. Then he unlocked one of the safes and drew out from an inner drawer a parchment book bound in brown vellum. He spread out the dispatch and read it carefully. It had been handed in at a town near the Belgian frontier about eight hours before:--
Fifty thousand camp bedsteads are urgently required for neighbourhood of La Guir. Please do your best for us, the matter is urgent. Double mattress if possible. London.
For a matter of ten minutes Thomson was busy with his pencil and the code-book. When he had finished, he studied thoughtfully the message which he had transcribed:--
Plans for attack on La Guir communicated. Attack foiled. Believe Smith in London.
“Anything important, sir?” the young man at the typewriter asked.
Thomson nodded but made no immediate reply. He first of all carefully destroyed the message which he had received, and the transcription, and watched the fragments of paper burn into ashes. Then he replaced the code-book in the safe, which he carefully locked, and strolled towards the window. He stood for several minutes looking out towards the Thames.
“The same thing has happened again at La Guir,” he said at last.
“None. They say that he is in London now.”
The two men looked at one another for a moment in grave silence. Ambrose leaned back in his chair and frowned heavily.
“Through our lines, through Boulogne, across the Channel, through Dover Station, out of Charing-Cross, through our own men and the best that Scotland Yard could do for us. In London, eh?”
Thomson’s face twitched convulsively. His teeth had come together with a little snap.
“You needn’t play at being headquarters, Ambrose,” he said hoarsely. “I know it seems like a miracle but there’s a reason for that.”
“Only a few weeks after the war began,” Thomson continued thoughtfully, “two French generals, four or five colonels, and over twenty junior and non-commissioned officers were court-martialled for espionage. The French have been on the lookout for that sort of thing. We haven’t. There isn’t one of these men who are sitting in judgment upon us to-day, Ambrose, who would listen to me for a single moment if I were to take the bull by the horns and say that the traitor we seek is one of ourselves.”