Prior to World War II he had been a theological student, but soon after its outbreak he enlisted in the Royal Artillery and Parachute Regiment.
[1] His council ward was very safe for the Labour Party, although the constituency that it was situated in – Liverpool Toxteth – was a marginal seat for the Conservatives from its creation in 1950.
In parliament he was a strong supporter of the Territorial Army, and on one occasion voted against the annual Defence Estimates because they failed to make a large enough provision for it.
Notionally a safe Labour constituency, Crawshaw's candidacy was further complicated by the existence of an Independent Liberal on the ballot.
During his time in Parliament he lived in Chelsea with fellow Liverpool Labour MP James Dunn, who also joined the SDP.