by Guglielmo Marconi in 1897 in Britain, originally under the name of The Wireless Telegraph & Signal Company. Following GEC's acquisition of Marconi as part of English Electric in 1968, the Marconi brand was used for its defence businesses, e.g. Marconi Space & Defence Systems (MSDS), Marconi Underwater Systems Ltd (MUSL).

When it was acquired by GEC, MES represented the pinnacle of the company's defence businesses, which had a heritage of almost 100