Although he was dismissed twice from the RCA painting school over conflicts with its then anti-modern stance, his early works were accepted by the London Group, with whom he exhibited from 1927 to 1932.
In 1936 he joined the publicity department of the Asiatic Petroleum Company (part of the Shell corporation) though continuing his socialist and anti-war involvement, such as exhibiting with the AIA during the Spanish Civil War.
During World War II, Boswell was called up in 1941, initially training in Scotland as a radiographer in the British Royal Army Medical Corps.
His pre-war satirical style has been described as "attractively pugnacious" and compared to the work of the German artists George Grosz and Otto Dix and to British artist/illustrators such as Edward Ardizzone.
[5] While in Iraq he also produced a series of fierce surreal sketches graphically illustrating his view of war more symbolically:[7] "a bestial farce conducted by bulls.
They ride on the backs of exhausted Tommies, pause with a watering-can to sprinkle a flower-pot containing the grotesquely dismembered skeleton of a soldier and sit on a hideous pile of corpses and ruined buildings while they type out a mass of documents which sail ridiculously into the sky.