The Royal Corps of Signals was founded in 1920 with a responsibility for the Army’s communications. It encompassed many of the roles previously undertaken by the Royal Engineers or regimental signals units. Appropriately enough the Corps chose as its cap badge the figure of Mercury, messenger to the gods in Roman mythology. The figure was soon christened ‘Jimmy’ by the soldiers of the Corps. The exact origins of why this name stuck is unclear, but general opinion is the name Jimmy comes from a Royal Signals boxer, called Jimmy Emblem, who was the British Army Champion in 1924 and represented the Royal Corps of Signals from 1921 to 1924. At the outbreak of World War II the cap badge took the form of a white metal Mercury standing on a globe, representing the Corps’ role around the world and on every battlefield. This emblem was mounted on a gilding oval with the Corps’ name on it and surmounted by the King’s Crown:

The cap badge was updated in 1946 and did away with the oval and mounted the crown separately above Mercury, but this badge is the design used throughout the interwar period and the Second World War.

The rear of the badge has the usual slider to allow it to be mounted to a variety of headwear:

The cap badge can be seen being proudly worn on service dress caps, field service caps, general service caps and berets throughout the Second World War: