In the empty aircraft hanger the evening air was bitter cold. Gathered beside a collection of large objects draped in grey sheets were the MI5 Chief of Operations, the Field Agent assigned to research this alien undercover op, the elderly man whose name or role was never specified, and a man in a white coat – who was the only one smiling, in a way guaranteed to make onlookers uneasy. There came the sound of vehicles and of booted feet marching in unison into the hanger. Into view trooped twenty soldiers: the special forces team chosen for this madcap endeavour. ‘Halt!’ cried the man at the head of the block of men, and, as the Field Agent could now see, at least three women. The Chief of Operations cleared his throat, ‘Welcome. I believe you have had a general briefing on tomorrow’s mis

