The Royal United Services Institute (RUSI) is a defence and security think tank based in Whitehall, London. Founded in 1831 by the first Duke of Wellington, it is described as the world’s oldest defence and security think tank.

In coverage of Starlink’s role in Ukraine’s war effort, RUSI military sciences associate fellow Thomas Withington said the system supports communications between frontline units and distant commanders. He also described restrictions on its use as a serious potential hindrance to Ukraine’s operational communications and drone operations.