[3] While visiting relatives in Hamburg in 1914, he was arrested by the German authorities and interned at Ruhleben, outside Berlin, as a civilian prisoner for the duration of the First World War.

During his captivity Brose became interested in Einstein's Theory of Relativity, realised its significance and, while he was still at Ruhleben, started translating two books on General Relativity that had just recently appeared: philosopher Moritz Schlick's Space and Time in Contemporary Physics and astronomer Erwin Freundlich's The foundations of Einstein's Theory of Gravitation.

He went on to do research on spectrophotometry at the Clarendon Laboratory, headed by Frederick Alexander Lindemann who also agreed to supervise Brose's doctoral work entitled 'A critical study of the development of the theory of relativity'.

During the war, contacts between the scientific communities of the belligerent countries had broken down; as a consequence, not more than a handful of English physicists had so far even heard about Einstein's gravitational theory.

Lindemann was delighted with Brose's knowledge and arranged for him to give a lecture on General Relativity to the Science Colloquium at the Clarendon.

Encouraged by the physiologist John Scott Haldane (who had been in the audience), Brose went on to publish his lecture by the title: The Theory of Relativity: An Introductory Sketch based on Einstein's Original Writings (Blackwell, Oxford 1919).

[1] This changed in November 1919, when the results of the Eddington experiment were made public, confirming Einstein's Theory of General Relativity.

During the war, the Cambridge astronomer Arthur Stanley Eddington had learned about Einstein's new theory through the Dutch physicist Willem de Sitter.

Together with Frank Watson Dyson, he had mounted expeditions for putting one of its predictions - the deflection of light in a gravitational field - to the test, on the occasion of the eclipse of May 1919.

Despite his intense translational work on the theory of relativity and quantum physics, Brose's own interests as a physicist turned out to be more of the experimentalist kind.

Ellis, Lawrence Bragg and Hatfield.′[3] It was also thanks to Brose’s untiring efforts that, on 21st June 1930, Einstein finally appeared in person at Nottingham University, where he gave a talk on 'Space and Matter’ in which he outlined his ideas on a unified field theory.

Brose's contributions to the introduction and dissemination of crucial German works of modern physics in Britain have been essential for the scientific and intellectual discourse of their time.

Nowadays it is known that chemical blood tests cannot diagnose cancer, but at the time, Brose performed well, his findings were published in numerous papers, and he also developed simplified methods for comparing the intensity of medical x-rays.

[3] But after producing lackluster results, the Cancer Research Committee was disbanded in 1938, and much of the value of Brose's work was lost by his unwise reaction to this closure.

Despite a tribunal the following month finding no evidence of disloyalty, it stated that Brose was;[3] a thoroughly unscrupulous person, and quite devoid of moral or ethical inhibitions.

Moreover he is possessed of marked energy and mental capacity and in need of money...given the opportunity, he could undoubtedly be a great potential danger to this countryAlthough many submissions were made in Brose's favor, he remained interned at Orange until late 1943, when he was allowed to work as a labourer in Terrigal.

[3] Having lost the support of his university and colleagues, and embittered by his second experience of captivity, Brose never again worked in scientific research.