All councils should demand 10 years checkable work history (like 'proper' security companies), and obviously full enhanced CRB check certificate (which I have), plus English language and local knowledge test.
Big picture ID posted in prominent place in the car.
- Both for Hackneys and 'Minicabs'.
Hopefully this would weed out most of the dubious characters/illegals.
You only have to consider recent murder and rape cases to appreciate the importance of this. Passengers are putting their lives in the drivers hands after all