It was December 1996 and my father had just bought a copy of John le Carré's newly published spy thriller, The Tailor Of Panama. When he saw that the book's hero had almost the same surname as him, he smiled. But the further he read, the more the coincidences began to pile up, and by the time he'd reached the end, he was astonished. This wasn't a fictional spy tale, he told himself. This was the story of his own father's life. Dad was amazed but also angry. He had known that his father worked for the Secret Intelligence Services, also known as MI6, in the Second World War, but when he had tried to get hold of a copy of his file, he'd been told it didn't exist.