Number 617 Squadron is a Royal Air Force aircraft squadron, originally based at RAF Scampton in Lincolnshire and currently based at RAF Marham in Norfolk. It is commonly known as the "Dambusters", for its actions during Operation Chastise against German dams during the Second World War. In the early 21st century it operated the Panavia Tornado GR4 in the ground attack and reconnaissance role until being disbanded on 28 March 2014. The Dambusters reformed on 18 April 2018, and was equipped at RAF Marham in June 2018 with the Lockheed Martin F-35B Lightning, becoming the first squadron to be based in the UK with this advanced V/STOL type. The unit is composed of both RAF and Royal Navy personnel, and operates from the Royal Navy's Queen Elizabeth-class aircraft carriers.

Operation Chastise was an attack on German dams carried out on the night of 16/17 May 1943 by 617 Squadron RAF Bomber Command, later called the Dam Busters, using special "bouncing bombs" developed by Barnes Wallis. The Möhne and Edersee dams were breached, causing catastrophic flooding of the Ruhr valley and of villages in the Eder valley; the Sorpe Dam sustained only minor damage. Two hydroelectric power stations were destroyed and several more damaged. Factories and mines were also damaged and destroyed. An estimated 1,600 civilians – about 600 Germans and 1,000 forced labourers, mainly Soviet – were killed by the flooding. Despite rapid repairs by the Germans, production did not return to normal until September. The RAF lost 53 aircrew killed and 3 captured, with 8 aircraft destroyed.