1951 - Electronics Division started at Ilford

1955 - the Electronics and Equipment Group was set up.

c.1961 - The Plessey Company set up four other businesses: Telecommunications Division, Plessey Avionics and Communications, Plessey Radar (Weybridge) and Plessey Marine.

1988 - Plessey and The General Electric Company (GEC) merged their telecom units to form GEC-Plessey Telecommunications (GPT) with the ownership then split with Siemens AG in 1989.