As a first assistant director, he worked on a number of high-profile films, including the Star Wars and Indiana Jones series and the 1978 Superman, and with commercially and critically successful directors including Richard Attenborough, George Lucas, Steven Spielberg and Sydney Pollack.

[1] He worked on numerous productions, and (with an interruption for National Service in the Royal Marines), became a First Assistant Director in 1954.

[1] As well as films, he worked on a number of British-made TV series, including William Tell, One Step Beyond, The Count of Monte Cristo, The Adventures of the Scarlet Pimpernel, Douglas Fairbanks, Jr., Presents and The Invisible Man.

Tomblin worked as a director on Gerry Anderson's live-action productions UFO, The Protectors and Space: 1999.

[3] With Richard Attenborough, he was named as a winner of the 1982 DGA Award for Outstanding Directorial Achievement in Feature Film for Gandhi.