Before Bletchley Park could break the German war machine's code, its daily military communications had to be monitored and recorded by 'the Listening Service', the wartime department whose bases moved with every theatre of war (Cairo, Malta, Gibraltar, Iraq, Cyprus) as well as having listening stations along the eastern coast of Britain to intercept radio traffic in the European theatre. This is the story of the - usually very young - men and women sent out to farflung outposts to listen in for Bletchley Park, an oral history of exotic locations and ordinary lives turned upside down by a sudden remote posting - the heady nightlife in Cairo, filing cabinets full of snakes in North Africa, and flights out to Delhi by luxurious flying boat.