The Lightning was 'developed' from the P1 series of research aircraft. Design considerations for research aircraft do not include long term operational use, nor the need for much fuel!!
The P1 happened to be around when somebody decided we needed a supersonic interceptor and this was seen as a ready means of generating something to meet the requirement. Unfortunately, the system failed to grasp the need to re-design fully the aircraft engineering aspects to meet the needs of an operational platform. The Lightning was a nightmare for Sqn Engineers. Rectifying anything in the fuselage invariably required at least the Jet-Pipes to come out and often one or both engines. Fuel leaks plagued the aircraft throughout its service life and several were lost due to fuel fires in flight. I can recall a time when 56 Sqn in Cyprus had all its airframes grounded with Cat 3 Fuel Leaks. We loaned one of ours to 56's aeros pilot to keep him current, after landing that was also Cat 3 Fuel Leaks - our Boss was not amused!
It was generally accepted a Lightning required 50 hours of engineering support to generate a single flying hour.
lm