The Welsh-born actor, who is best known for his starring role in 1960s sci-fi drama A for Andromeda, spent almost 60 years in showbusiness.
Halliday became a professional actor after serving in World War II. He joined the Shakespeare Memorial Theatre in Stratford-upon-Avon, England in 1950 and worked alongside great thespians like Richard Burton and Sir Ralph Richardson.
During his career, he appeared on cult TV shows Dr Who, The Sweeney, The Saint and The Avengers.
He also featured in the films The Swordsman and Remains of the Day.
His final movie was 2005's star-studded Lassie, in which he played a vicar.