Plessey

Plessey

Company type	Public company
Industry	Electronics, defence and telecommunications
Founded	1917
Defunct	1989
Fate	Acquired (in 1989 by GEC/Siemens joint holding company – GEC Siemens)
Successor	GEC (1989–1999) Siemens Plessey (1989–1997) Marconi Communications (1998–2006) Siemens Communications (1998–2006) BAE Systems (1999 till date) Plessey Semiconductors (2010 till date)
Headquarters	Ilford, London, England
Key people	Sir John Clark (chairman)

The Plessey Company plc was a British electronics, defence and telecommunications company. It originated in 1917, growing and diversifying into electronics. It expanded after World War II by acquisition of companies and formed overseas companies. It was listed on the London Stock Exchange and was a constituent of the FTSE 100 Index. In 1989, it was taken over by a consortium formed by GEC and Siemens which split the assets of the Plessey group.

The majority of Plessey's defence assets were amalgamated into BAE Systems in 1999 when British Aerospace merged with the defence arm of GEC, Marconi Electronic Systems (MES). The Plessey Microsystems division was the subject of a management buyout in 1988^[1] becoming Radstone Technology, which survives today as part of Abaco Systems based in Towcester, Northamptonshire. The bulk of Plessey's telecommunications assets were acquired by Ericsson through its 2005 acquisition of Marconi Communications, a successor company of GEC.