"One of the primary roles for the RAF is air defence of the United Kingdom. The Air Surveillance and Control Systems (ASACS) Force is responsible for compiling a Recognised Air Picture, monitoring the airspace around the UK and providing tactical control of the Quick Reaction Alert Force. Tornado F3s and Typhoon F2s are held at a continuous ground readiness posture at RAF Leuchars in Fife and RAF Coningsby in Lincolnshire. Where there are indications that an aviation security incident might develop, the crews are brought to cockpit readiness allowing aircraft to take off within minutes, thus allowing us to provide a good response across the country to defend against potential hostile threats."