Siebe plc became the name of the new conglomerate formed when Siebe Gorman began taking over other firms in the early 1970s, to distinguish it from Siebe Gorman's original breathing apparatus and diving gear core business. Siebe plc was once one of the United Kingdom's largest engineering businesses and was a constituent of the FTSE 100 Index. In 1999 it merged with BTR plc to form Invensys. History About 1972: Siebe plc became the name of the new conglomerate formed when Siebe Gorman began taking over other firms, to distinguish it from Siebe Gorman's original breathing apparatus and diving gear core business. 1972: Siebe plc acquired James North & Sons, a large safety products business, and continued to brand it as North Safety Products. 1985: Siebe plc acquires CompAir, a business making compressed air equipment for the mining and construction industries, divers and firefighters. 1987: Siebe plc acquires the Barber-Colman Company, an industrial automation and controls business. 1990: Siebe plc acquires the Foxboro Company, another industrial automation business. 1994: Siebe plc bought Triconex, a safety control business. 1997: Siebe plc acquired APV plc. 1998: Siebe plc acquired Eurotherm, Wonderware and Simulation Sciences. 1998: Siebe plc sold North Safety Products (and Siebe Gorman with it) to Norcross. 1999: Siebe plc acquired Esscor. 1999: Siebe plc merged with BTR plc to form Invensys. References Defunct manufacturing companies of England Defunct companies based in London Manufacturing companies based in London British companies established in 1972 Manufacturing companies disestablished in 1999 1972 establishments in England 1999 disestablishments in England Companies formerly listed on the London Stock Exchange British companies disestablished in 1999