> Couldn't somebody borrow a friend's black cab, slap on a fake photo, and work the city?
There is concern that this is happened in the past and penalties are extremely severe: the owner of the original license will lose their badge and may face criminal charges.
It's a bit hard to describe the taxi market in London to anybody who doesn't live here, but it's a closed shop only to the extent that if you're prepared to do the work to get a badge, it won't cost you $1m like New York, but you will have to put some hours in, and you'll get known by many other black cab drivers.
If you show up with "Dave's cab" and you're not Dave, you're going to get asked questions. Do it a couple of times, and they might decide to pull your badge number up.
A few years ago a genuinely licensed black cab driver was convicted of rape and sexual assault, and as a result the community was shaken: it was the first time in over 300 years where a licensed operator had been convicted of such a crime, and they now look on newcomers with even more suspicion.
There are no lobbyists in parliament, and most black cab drivers I know have modest incomes. They declare an average of £38k/year, but as a cash business (until recently), it was assumed they were actually doing about £50k/year. Good money, but not megabucks.
The system is supported because it's worked for hundreds of years. Their chief complaint against Uber is whether their drivers have to undergo the same amount of vetting as they had to (they don't), and whether the fare structure is fair (it isn't, especially as it's VC-subsidised).
Uber is a great solution in many places that have poor transit and poor taxi solutions already. London isn't one of those places, and hasn't been for hundreds of years.