Ian Kennedy Martin (born 23 May 1936) is a British television scriptwriter. He is best known for his creation of the popular 1970s police drama series The Sweeney, produced by Euston Films for Thames Television, which ran on the ITV network from 1975 to 1978. It also spawned two feature film spin-offs. He is also known for writing the 1975 action film Mitchell.
He began his television career in the 1960s, first as a script editor on the military police drama series Redcap (1964) and then later as a writer on series such as The Troubleshooters (1965). In 1971 he worked on the popular BBC drama series The Onedin Line, which ran for nine years until 1980. He also wrote the 1974 drama series The Capone Investment.
Since the end of The Sweeney in 1978, Kennedy Martin has continued to write for various police / detective dramas. These have included the BBC's Juliet Bravo and The Chinese Detective during the 1980s and ITV's The Knock in the 1990s. He has also written a number of novels, including Rekill and the dystopian science fiction novel The Last Crime, this last under the pseudonym John Domatilla. On 9 March 2009, his first play, The Berlin Hanover Express premiered at the Hampstead Theatre in North London.