Evidence of illegal drugs being used by children as young as 14 attending supposedly "safe" all-night raves has been uncovered by a BBC London investigation.

Let's Go Crazy (LGC) is a popular clubbing event which markets itself as a safe night out for over 16s where drugs will not be tolerated.

It hires out venues across London for its all-night events.

A spokesman for LGC said: "We treat all allegations of substance abuse seriously and we will investigate fully what occurred to ensure any issues are resolved before another event takes place."