In many parts of the country, including the whole of south-east England for example (where a majority of UK pilots fly), it is perfectly possible to fly at night without any instrument experience.
I suggest a study of the circumstances surrounding JFK Jr's death.
As I recall the theory has it that he was flying from an area that had lights visible to a sparsely inhabited area with few or no lights visible. What he saw was the lights disappearing under the nose as he passed over them. With no more lights in view ahead the visual cues were similar to those he would have got had the aircraft pitched up. He lowered the nose to compensate and the aircraft descended rapidly into the sea.
Had he been in current instrument practice he might have deduced from his instruments that his brain was misinterpreting the visual clues and might not have died.
There are many reasons why you might lose sight of ground lights in the UK at night. Radiation Fog and low cloud are two that spring immediately to mind. There are also plenty of areas where in a slant visibility of say 5 miles you might get exactly the same effect happening to you even if there was no obscuring clound or fog. Flight over the New Forest or estuaries for example.
Mike