He was born Roger Middleton in Sheffield at the outbreak of World War II, and studied acting at the Central School of Speech and Drama. He took his stage name from that of an earlier film actor called Maurice Colbourne, (24 September 1894 – 22 September 1965), who shared the same date of birth (in a different year) as his. He first became well known when he played the lead in a BBC drama series, Gangsters, from 1975-78, and afterwards appeared regularly on screen.
He twice appeared in the science fiction series Doctor Who as the character Lytton; in Resurrection of the Daleks (1984) and Attack of the Cybermen (1985). He also appeared in the television miniseries adaptation of John Wyndham's The Day of the Triffids (1981), as the character Jack Coker.
In 1972 he co-founded, together with Mike Irving and Guy Sprung, the Half Moon Theatre in Aldgate, East London. This was a successful, radical theatre company, performing initially in an 80-seat disused synagogue near Half Moon Passage, E1. In 1985 the company moved to a converted chapel in Mile End Road, near Stepney Green.
He is probably best remembered as Tom Howard, in the BBC Television serial, Howards' Way, which he played from 1985-89, until he died suddenly aged 49 of a heart attack while renovating a holiday home in Dinan, Brittany, France.