Marconi Electronic Systems (MES), or GEC-Marconi as it was until 1998, was the defence arm of The General Electric Company (GEC). It was demerged from GEC and acquired by British Aerospace (BAe) on November 30, 1999 to form BAE Systems. GEC then renamed itself Marconi plc.
MES exists today as BAE Systems Electronics Limited, a subsidiary of BAE Systems, but the assets were rearranged elsewhere within that company. MES-related businesses include BAE Systems Submarine Solutions, BVT Surface Fleet, BAE Systems Insyte and SELEX Sensors and Airborne Systems (now owned by Finmeccanica).
BAE Systems plc is a British defence, security and aerospace company headquartered in Farnborough, Hampshire, England, that has global interests, particularly in North America through its subsidiary BAE Systems Inc. BAE is the world's second-largest defence contractor and the largest in Europe. It was formed on 30 November 1999 by the £7.7 billion merger of two British companies, Marconi Electronic Systems (MES), the defence electronics and naval shipbuilding subsidiary of the General Electric Company plc (GEC), and aircraft, munitions and naval systems manufacturer British Aerospace (BAe).
BAE is the successor to various aircraft and defence electronics companies, including The Marconi Company, the first commercial company devoted to the development and use of radio; A.V. Roe and Company, one of the world's first aircraft companies; de Havilland, manufacturer of the world's first commercial jet airliner; British Aircraft Corporation, co-manufacturer of the Concorde supersonic transport; and Supermarine, manufacturer of the Spitfire. It has increasingly disengaged from its businesses in continental Europe in favour of investing in the United States. Since its formation it has sold its shares of Airbus, EADS Astrium, AMS and Atlas Elektronik.