Lieutenant Colonel David Michael Callum MRCS LRCP DPM was the Regimental Medical Officer of both 3 PARA and 4 PARA.

He was born in 1936 and first commissioned in 1962 into the Royal Army Medical Corps. He was promoted to Captain on March 11, 1963 on a short service commission. He later advanced to Major on July 16, 1967 on another short service commission. These posts were later updated to a long term commission in the RAMC on October 6, 1975, with backdated seniority. 

Further information was provided to the Airborne Network by Brig Alistair Macmillan (late RAMC):

"As I recall he was 3 Para's RMO in his time, but I first met him in 1973 during the Bruneval Cup Competition (44 Para Bde's Annual First Aid Competition). He had finished his SSC and was 4 Para's RMO. 15 Para had just donated a Pearson Trophy for a new competition, to coincide with the Bruneval, and it was for the best RAP. I think John Gibbons had 10 Para's RAP out as well. For the record 15 Para's RAP won. He later remustered as a Psychiatrist."

Callum was promoted to his final rank of Lieutenant Colonel on May 4, 1977. He retired on September 21, 1987. He later became a Consultant Psychiatrist and was married to Patricia, with whom he had four children. He died at the age of 87 on December 1, 2023.