News & Facts about London bombings
Taken from sky news here
There has been an explosion at London's Liverpool Street Station, according to reports.
The blast happened at Aldgate East station on the Metropolitan and Circle Lines.
The explosion was caused by "some kind of power surge", according to Tube infrastructure company Metronet, which is responsible for maintaining the Metropolitan line.
A spokesman said: "We don't know the extent of the problem yet."
A London Ambulance Service spokeswoman said: "We have just sent some resources out to the scene."
British Transport Police confirmed that there are "walking wounded" and said paramedics have responded to one report of a person classed as "life at risk".
"It's chaos, with people trying to work out what has happened," said a spokesman.
"All we know at the moment is that staff reported a loud bang at 8.49am. No one is sure what caused an explosion, but it is thought it could have been a collision, a power cut, or a power cable problem."
King's Cross, St Pancras, Liverpool Street, Stratford and Aldgate East stations have all been evacuated.
I hope no one on here is affected. Was a nightmare getting in today, explains why