London Times report
This is how they said it affected the Tube:
London Underground said that 60 per cent of the network had been affected by the power cut along with thousands of passengers.
A spokeswoman said that staff had been forced to take passengers off trains stuck in tunnels.
"Stations and trains are being evacuated. Trains that are in tunnels will be de-trained. Staff will go down to the train and take them (passengers) down the tunnel bit by bit and make sure they get onto the platform and leave the station safely."
British Transport Police have said that power was slowly being restored to Tube lines. "Trains are slowly beginning to travel into places where they were stuck," said a spokesman.
"We are obviously having difficulty in contacting staff in the places which have been affected but things are now starting to move slowly."
The power cut came two weeks after a massive blackout brought the north east coast of America to its knees and prompted fears of a terrorist attack. There was no suggestion of a terror link to the London power cut.
Steve Bird, a Times reporter on the Underground, said that shortly after 6.15pm the packed southbound Northern Line train that he was travelling on lurched to an emergency stop moments after gathering speed after leaving Monument station.
A number of passengers were hurled to the floor by the force of the jolt.
The driver apologised and announced that there was a signal failure which he hoped would be repaired quickly.
After about 10 minutes he walked from his compartment through the carriages to the portion of the train which remained in the station.
While the passengers remained calm, many were puzzled by a repeated announcement played over the station Tannoy which could be heard in the distance which said: "Due to a reported emergency, all passengers are required to vacate the station."
Shortly before 6.30pm, the driver, who sounded tense, asked the passengers to walk to the back of the train where they would be able to leave the train and then the station.
Despite the calm way that the London commuters left, the carriages were littered with discarded bags of shopping and newspapers and magazines.
The passengers on the Northern Line, the deepest station at Monument, filed past empty trains on the District and Circle lines and spilled out in to the packed streets in the City.