The nationalisation of war, the rise of psychology, and the creation of 'spy fever' in the British press

‘Spy fever’ in Britain is often associated with suspicion and alarm arising from the potential threat of espionage around the time of the First World War. Yet the term first appeared in Britain during the Franco–Prussian War, as France’s experience of invasion was recounted in the press. By examining its broader etymology, this article highlights a neglected aspect of ‘spy fever’. The widespread use of medical terminology to describe popular reactions was intended, not as an accurate description of those behaviours and emotions, but as a way of ridiculing fears of secret enemies by likening them to psychological disorder.