In message , at 16:55:30 on Tue, 6 Oct
2015, JNugent remarked:

Are they perhaps (in London, anyway) "checking that a driver has been
vetted". The system in other cities may well be different.

No, it isn't.

The system is exactly the same in London and the rest of E&W: the
operator has to check that drivers to whom he sub-contracts (or
provides) work are licensed and insured.

Vetting also includes criminal records. And checking insurance on the
day they join doesn't guarantee they are insured the day after.
--
Roland Perry