The trains than can accelerate and brake more efficiently than those operated by a driver will be brought in under plans to boost the number of services at packed city centre stations.
Testing is currently being carried out on the Thameslink line through central London.
It is hoped that the introduction of self-driving trains will lead to services running every two and a half minutes, similar to the frequency on the London Underground, and a boost of up to 60 per cent.
Drivers will switch to automatic control between London Bridge and St Pancras stations.
But they will still be responsible for operating the doors and carrying out safety checks and will take full control of the trains outside central London stretching as far as Brighton and eventually Cambridge.
Self-driving trains are already used on the Tube, operating on four lines including the Northern and Victoria. There also plans to use them on the £14.8 billion east-west Crossrail route.
The plans to bring automated trains to the mainline rail network as part of the £6 billion Thameslink upgrade led by Network Rail were first reported by The Times.
Govia Thameslink Railway (GTR), which operates Thameslink, said the technology would reduce journey times and there was no chance of the train running through a red light.
Aslef, the train drivers’ union, has cautioned against the use of the technology on parts of the Victorian network outside of the capital.
Mick Whelan, general secretary, said: “Trains have to be driven; they don’t drive themselves, whatever science-fiction writers think. Even with increased automation, we will still want, and need, a trained driver at the pointy end of the train.”
The automatic system is to be used on a new generation of Class 700 trains built by Siemens and will work alongside a new signalling system which strips out lineside signals and places the technology directly into the drivers’ cab, the Times reported.
Nick Brown, chief operating officer for GTR, told the newspaper: “This is all about addressing the problem of congestion and massive growth in passengers.”