During the Second World War he was the chief scientist at the Royal Navy's Anti-Submarine Experimental Establishment in Fairlie, Scotland, where he oversaw the development of improved techniques for detecting submarines.

Roberts was briefly involved in the Rutherford's unsuccessful initial search for the neutron, but his main focus was on conservation of energy in hydrogen discharge.

In 1924 he developed a pain in his hip which was initially diagnosed as arthritis, but turned out to be tuberculosis, and he was hospitalised in a sanatorium in Switzerland for the next four years.

He became interested in functioning of the Pirani gauge, with which he investigated the thermal conductivities of gases, and of the heat conveyed to a gas by a hot wire.

He conducted ground-breaking research into the energy exchanges between hot metal surfaces and gases in contact with them, particularly hydrogen, and later oxygen.

[1][2] Soon after the outbreak of the Second World War in 1939, Roberts became a scientific advisor to the Royal Navy, working at the Naval Research Establishment on the River Clyde in Scotland and then at the Naval Research Establishment on the River Forth, where he developed techniques for degaussing ships to avoid magnetic mines, and for minesweeping.

He was elected a Fellow of Christ's College, Cambridge and harboured an ambition to one day direct the Mond Cryogenic Laboratory, but in March 1944 he developed a glandular infection, and then pneumonia, from which he did not recover.