GTR is warning people not to travel with Thameslink, Southern or Gatwick Express from the south into London this morning.
The train company said that it was due to the total loss of signalling power that Network Rail has experienced on three separate supplies in the Streatham area.
The problem affected hundreds of passengers as they tried to make it home from London last night (Wednesday 4 July).
There will be no services into Victoria from East Croydon or through the Streatham area as a result making other services that can run into other London stations extremely busy.
A GTR spokesman said: “Network Rail is working hard to rectify this fault but in the meantime passengers are urged not to travel from the south on our remaining services which will be heavily overcrowded.”
More as we get it.