In the 1960s, Movie magazine championed Holt as one of the finest talents working in the British film industry, although his output was notably sparse.

[3] He originally trained as an actor, and spent a term at RADA in 1940 before acting in repertory in Liverpool and Bideford in Devon working with Paul Scofield at the latter venue.

Holt received his first credit as editor on The Spider and the Fly (1949), made for Mayflower Pictures by Robert Hamer.

[4][10][11] After Ealing, Holt returned to editing on The Battle of the Sexes (1959) and wrote the script for a short film, Jessy (also 1959).

[12] In the Spring 1959 issue of Sight & Sound, he indicated a wish to make Gratz based on a book by J.P. Donleavy but that he also just wanted to practice his craft.

[13] Holt was reportedly responsible for saving Saturday Night and Sunday Morning (1960) and The Entertainer (1960), his last editing credits.

[17] Holt returned to Hammer to make The Nanny (1965), based on a script by Sangster and starring Bette Davis.

[22][better source needed] Holt directed episodes of Court Martial then made a James Bond-style thriller Danger Route (1967).

[27] He died on the film's set at Elstree Studios during production from a heart attack five weeks into the six-week shoot, collapsing with cast member Aubrey Morris preventing him from falling, according to Christopher Wicking's obituary in The Guardian.