I suspect there there is a lot of politics involved with the transport unions. They are very protective of the driver/security/conductor jobs. If TFL tried to r

I suspect there there is a lot of politics involved with the transport unions. They are very protective of the driver/security/conductor jobs. If TFL tried to remove the driver completely from a train, even on a new line, the unions will push back. From memory, one of the issues during the last few strikes was that TFL wanted to remove the conductor from some services, only having the driver who would then be responsible for safety. The unions strongly opposed it.