The Marconi Company Ltd. was founded by Guglielmo Marconi in 1897 as the Wireless Telegraph & Signal Company. The Marconi company should not be confused with the Marconi Corporation which was created in 1999 by the renaming of The General Electric Company (GEC).

The Marconi Company opened the world's first radio factory in 1899 and was responsbile for some of the most important advances in radio and television. English Electric acquired The Marconi Company in 1946 which complemented its other operations; heavy electrical engineering, aircraft and its railway traction business.

In 1968 English Electric was subject to a takeover bid by the Plessey Company but chose instead to accept an offer from GEC. The Marconi brand and operations were maintained as a major part of GEC, divisions of the company (at various times) included: Marconi-Elliot Avionics, Marconi Avionics, GEC-Marconi Avionics, Marconi Instruments Ltd, The Marconi International Marine Company, Marconi Communications, Marconi Marine (VSEL) and Marconi Electronic Systems.