Frederick Forsyth is in an elite band of thriller writers whose book titles are known the world over: the Day of the Jackal; the Dogs of War; Avenger. Forsyth's stories are told with a reporter's eye, which is unsurprising since he began his writing life as a foreign correspondent. From African coup plots to international drug trafficking, his books are rich in the detail of espionage, violence and dirty politics. Stephen Sackur asks him whether, in pursuit of a realistic plot line, he blurs the lines between fact and fiction.