Some technical clarifications:
the DLR is not driverless in the sense that people mean. They cannot operate without a train captain, and although the captain can give the start command from any location on the train, the train will not depart without him confirming the depart. This could probably be automated, however the system that the DLR uses is called Transmission Based Train Control (TBTC) signalling. This works by the the train continually communicating with the signalling system.
While for all normal operations this could be automated, the moment the train fails to communicate with the system (for a variety of reasons) it goes “non-communicating”. This can only be resolved by the -driver- sorry train captain on board manually taking over control of the train movements and moving outside of signalled protection (this is a potentially dangerous procedure and has strict protocols to protect it).
The Northern Line, the Jubilee Line, the Met line, the Hammersmith and City and the District line all use this same signalling system.
The Victoria line uses a variation called “Distance to Go-Radio”. It has differences but the fundamental similarity is the same. In the event the train stops communicating with the signalling system, it cannot be moved without manual control.
The DLR is not “unsafe” because it’s driverless. It has a driver. They’re just called a train captain instead.