The Spy Who Didn't Exist

Published in Ellery Queen Mystery Magazine, 12/1967.
British Intelligence is facing a crisis as the Russians claim to have intercepted messages from a British agent named Beaver, allegedly plotting assassinations. The problem? Beaver doesn't exist; he was a cover name invented for budgetary purposes by Colonel Nelson. Rand, from Concealed Communications, is tasked with resolving the issue before it sabotages a crucial disarmament conference.