Nationally in the UK thousands of drivers are exploiting the sub-contracting clause in the Deregulation Act 2015(section 55). This has allowed the situation whereby a person licensed in one authority can work as a PHV in any other authority in the country.
A good example of this exploitation would be; if a person took, and failed, a Knowledge test in one of the 316 Licensing authorities in the UK. This person could then choose to take a Knowledge Test in an authority with far fewer roads to learn, pass the test with ease, and then go back to work in the area they had originally failed in.
The rise in drivers working for "app based" companies has seen the situation where drivers licensed in London are working in different authorities nationwide.