Royal United Services Institute

The Royal United Services Institute is the world's oldest defence and security think tank, founded in 1831 by the first Duke of Wellington, based in Whitehall, London, United Kingdom. The institution was registered as Royal United Service Institute for Defence and Security Studies and formerly known as the Royal United Services Institute for Defence Studies. The current chair of RUSI is the ninth Duke of Wellington and its director-general is Rachel Ellehuus.