Somerset is an important supplier of defence equipment and technology. A Royal Ordnance Factory, ROF Bridgwater was built at the start of the Second World War, between the villages of Puriton and Woolavington, to manufacture explosives. The site was decommissioned and closed in July 2008. Templecombe has Thales Underwater Systems, and Taunton presently has the United Kingdom Hydrographic Office and Avimo, which became part of Thales Optics. It has been announced twice, in 2006 and 2007, that manufacturing is to end at Thales Optics' Taunton site, but the trade unions and Taunton Deane District Council are working to reverse or mitigate these decisions. Other high-technology companies include the optics company Gooch and Housego, at Ilminster. There are Ministry of Defence offices in Bath, and Norton Fitzwarren is the home of 40 Commando Royal Marines. The Royal Naval Air Station in Yeovilton, is one of Britain's two active Fleet Air Arm bases and is home to the Royal Navy's Lynx helicopters and the Royal Marines Commando Westland Sea Kings. Around 1,675 service and 2,000 civilian personnel are stationed at Yeovilton and key activities include training of aircrew and engineers and the Royal Navy's Fighter Controllers and surface-based aircraft controllers.

What is Somerset an important supplier of