Taxi regulations gives us passengers safety and fair prices.
Do not know about London. In my location all the money go to paying license fees and to the actual owners of Cabs (any entity with the money but the taxi driver). And how exactly exploiting taxi drivers makes us safer I have no idea.
Failure to do criminal background check is also pathetic lame excuse. I really doubt that said former criminal got into taxi driving job and paid all those fees in order to rob/assault passengers.