John Alfred Terraine (15 January 1921 – 28 December 2003) was a TV screenwriter, and leading British military historian, although not permanently associated with any academic institution. He is best known for his persistent defense of British General Douglas Haig, "the Butcher of the Somme", and also as the lead screenwriter for the landmark 1960s BBC-TV documentary The Great War. A quote from one of his books, ''The Smoke and the Fire'' (1980) is used by the WJEC as a source for GCSE history coursework.
Terraine was born in London. He was educated at Stamford School and at Keble College, Oxford.
In 1945 he married Joyce Waite; they had one daughter.
After leaving Oxford in 1943, he joined BBC radio and continued to work for the BBC for 18 years, ending as its Pacific and South African Programme Organiser. After resigning from the BBC in 1961, Terraine worked as a freelance television screenwriter. Among other series, Terraine was associate producer and chief screenwriter of the 1963-64 BBC-TV documentary The Great War, and co-wrote its sequel The Lost Peace (1965). For Rediffusion and Thames Television he wrote The Life and Times of Lord Mountbatten (1966–68) and Lord Mountbatten: A Man for the Century (1969), and later collaborated with Mountbatten on an illustrated biography based on the series. Terraine found Mountbatten an impressive performer, but was intrigued by his "curious mix of boastfulness and diffidence". Terraine wrote and narrated The Mighty Continent (1974–75), an impressive 13-part BBC-TV history of Europe in the first three quarters of the 20th century.
Terraine published 16 books, most of them dealing with aspects of the great European wars of the 20th century, and numerous articles and book reviews for The Daily Telegraph. His first major study of the First World War, Mons: The Retreat to Victory was published in 1960. In 1964 Terraine edited a collection of diaries written by General James Lochhead Jack during the First World War, which became a bestseller in the United Kingdom. The Right of the Line: The Royal Air Force in the European War 1939-45 (1985) won the Yorkshire Post Book of the Year award. His last book Business in Great Waters: The U-Boat Wars, 1916-1945 was published in 1989.