
From Wikipedia:
Neil John McCallum (1929–1976) was a British-Canadian actor. After attending the Guildhall School of Music and Drama in London, McCallum's first major appearance on stage was alongside Sam Wanamaker in The Rainmaker in the mid-1950s.[3] He appeared in British TV series in the 1950s, 1960s and early 1970s, including The Saint, Department S and UFO, and in films such as The Siege of Pinchgut (1959) and Dr. Terror's House of Horrors (1965).[4] He provided the voices of Dr Ray Pierce in the film Thunderbirds Are Go (1966) and an airport controller in the TV series Captain Scarlet and the Mysterons (1967).[5] He played lead character Angelo James in the BBC TV series Vendetta (1966-68).
He was also a scriptwriter (scripting two 1964 thrillers, Do You Know this Voice? and Walk a Tightrope, among other things), a producer and occasional director.

The Longest Day
1962 · as Canadian Doctor (uncredited)

The Devil's Disciple
1959 · as Christie Dudgeon

The War Lover
1962 · as Sully

Dr. Terror's House of Horrors
1965 · as Jim Dawson

The Inspector
1962 · as Browne

Quest for Love
1971 · as Jimmy

The Lost Continent
1968 · as First Officer Hemmings

Foxhole in Cairo
1960 · as Sandy

Moon Zero Two
1969 · as Space Captain

Jet Storm
1959 · as Gilbert

Thunderbirds Are GO
1966 · as Dr. Ray Pierce (voice)

Catacombs
1965 · as Richard 'Dick' Corbett

The Siege of Pinchgut
1959 · as Johnny Kirk

The Scent of Fear
1959 · as Karl Schling

Walk a Tightrope
1963 · as Counsel

On the Run
1958 · as Wesley

Captain Scarlet vs. The Mysterons
1980 · as Delta-Tango 19 Pilot / Airport Controller (voice)

Hazard
1959 · as Syd