Harry,
so we are not talking about regulation, but about enforcement of regulation. Those are two different things.
However, can you be sure that, for example, the CAA has a resident inspector at various European airports from which bmi regional operates without ever touching UK soil - eg. the sizeable network they operate out of MUC, the routes operated to France and Belgium by a BRE-based aircraft, or their operation in the Swedish wilderness? Could be, but I doubt it.