1988 GEC and Siemens AG set up a jointly held company, GEC Siemens plc, to launch a hostile takeover of Plessey. GEC Siemens' initial offer was made on 23 December 1988 valuing Plessey at £1.7 billion. Plessey rejected the offer and it was referred to the MMC. The original proposal envisaged joint ownership of all of Plessey's defence businesses, with GPT and Plessey's North American businesses split in the ratios 60:40 and 51:49 respectively. The level of GEC's involvement in the Plessey defence businesses was not likely to meet with regulatory approval.
1989 After reference to the MMC, in February GEC Siemens announced a new bid. The takeover was completed in September 1989. GEC expected to acquire about 40 percent of the Plessey businesses (by value)[1]
August 1998 GEC acquired Siemens' 40 percent stake in GPT and merged with the telecoms units of its Italian subsidiary Marconi SpA, GEC Hong Kong and ATC South Africa to form Marconi Communications.
1997 in the UK, the name GPT disappeared; the company was called SGCS (Siemens GEC Communication Systems) which was a JV of GEC and Siemens AG combing GPT with Siemens Business Communication Systems[2]