London: Collins, 1967. Hardcover. 223p., very good first UK edition in boards and unclipped dj with mild toning to edges, jacket design by Michael Whittlesea. Spy thriller with gay theme. Young 2387 A Collins Novel of Suspense.
Basis of the Dirk Bogard/Ava Gardner film "The Executioner" aka "Permission to Kill" W.I.L. = Western Intelligence Liaison.