London Bridge station has been evacuated.
Loud alarms were sounded inside the station and everyone inside was moved out by police, at around 10.30am.
The station is now being re-opened, British Transport Police tweeted.
Officials were responding to a fire alarm, according to reports on the ground.
The station is in the heart of central London and among the busiest on the entire rail network.
Train services into and out of the station were subject to severe disruption and cancellations while authorities respond to the alarm.
Tube services at London Bridge underground station were not affected, according to Transport for London.
