Aircraft was caught in a cone of 40/50 Searchlights. Hit by flak damaging hydraulic system and somewhere in the brake system. At enemy coast two starboard engines packed up. Owing to having no radiator flaps and port engines overheating aircraft was forced to lose height. A landing was attempted at Bircham Newton, but one or both tyres were punctured and aircraft overshot flarepath. The undercarriage collapsed and the aircraft came to rest about half a mile from aerodrome.