Thomas and educated at Grove Park School, Wrexham and Downing College, Cambridge.

[3] During World War I he served a Photographic Officer in the Royal Flying Corps in Europe and the Middle East.

Dr Thomas is well known as an authority on aircraft photography and was one of the first to demonstrate its application to the survey of vegetation.

Whilst being shown around the PI centre at Medmenham, after being at a meeting including Hamshaw Thomas, afterwards, out of earshot, South African Prime Minister Jan Smuts turned to his companion and said; "Do you know, that fellow" - (referring to Hamshaw Thomas) - "is the world's leading palaeobotanist" - Smuts was a renowned botanist himself.

As "Chief of Third Phase Interpretation", in 1943 it was Hamshaw Thomas who was responsible, along with his Army opposite number, Major Norman Falcon, for initiating the Allied investigation of the German research centre at Peenemünde[5] He died in Cambridge in 1962.