In 1969 under Robert Telford, Managing Director of GEC-Marconi Electronics, four new market oriented management companies were established each covering the activities of a group of existing GEC-Marconi companies. As a result the Company became Marconi-Elliott Avionic Systems Ltd comprising the Rochester and Borehamwood activities of Elliott Flight Automation, Elliott-Automation Radar Systems and the Basildon activities of the Marconi Aeronautical Division together with the Electro-Optical Systems Division. Dr Bernard O’Kane was Managing Director with Jack Pateman as Deputy Managing Director.
In 1978 the company was renamed Marconi Avionics Ltd with Dr Bernard O'Kane, Chairman and Jack Pateman, Managing Director. Once again the Company won a Queen’s Award for Export and with the continued growth a new Building to be called the Corsair Building was opened in August 1978. By 1980 the new Phase III Building dedicated to the growing business in flight controls was operating and the Automatic Test Equipment Division was established in yet another building..
There was steady growth to nearly 12,000 employees in 1982. The name was again changed to GEC Avionics Limited in September 1984 although it was not until four years later that the trading name of Elliott Bros London was finally dropped.
In 1993 yet again the company name changed to GEC-Marconi Avionics Ltd comprising the former GEC Avionics, GEC-Ferranti Defence Systems, GEC Sensors and GEC Aerospace businesses. This organisation was announced on 5 January 1993 and came into effect on 1 April 1993 and finally in 1998 it became Marconi Electronic Systems Ltd.
At the end of 1999 Marconi Avionics was absorbed into BAE SYSTEMS with the merger of British Aerospace and Marconi Electronic Systems.