Dozens of firefighters are battling a blaze at Westminster Staton after evacuating around 100 people.
Six fire engines, around 40 firefighters and a number of police officers have rushed to the scene in central London.
Nearby members of the public have been evacuated and the tube station is now closed.
Officers have set up a cordon around the scene, which is just metres away from Parliament.
London Fire Brigade tweeted: “Six fire engines and around 40 firefighters are at the scene of a fire at Westminster Station on Bridge Street in #Westminster. More information to follow.”
Crews were called at just before 11.30am to reports of smoke coming from an electrical room within the station.
A spokesman for the fire brigade said: “Six fire engines and around 40 firefighters have been called to smoke issuing from an electrical room at Westminster Station on Bridge Street in Westminster.
“Firefighters are currently at the scene and investigating a large amount of smoke coming from an electrical room within the basement of the station
“The Brigade was called at 11.29am. Fire crews from Lambeth, Euston, Old Kent Road and Soho fire stations are at the scene.”
The fire brigade confirmed 100 people had been evacuated from Westminster Station.
In a later tweet, the LFB said the incident was ‘now under control’.
A spokesman for British Transport Police said: “We were called to Westminster station 11.31am following reports of a fire alert. Officers are assisting London Fire Brigade and the station has been closed.”
One Twitter user, who shared footage of firefighters at the scene, tweeted: “Fire at Westminster underground station in London – Firefighter confirms there is a fire 10 stories down, tricky to get to but all under control.”
It comes after the LFB was forced to pump water out of properties flooded in Westminster this morning.
Westminster Council tweeted: “Due to heavy rainfall overnight and early this morning, parts of Knightsbridge, Bourne Terrace (W2), Oak Tree and Abbey Road (NW8) have been flooded. City inspectors are currently in these areas to assess which properties have been affected.
“London Fire Brigade are on site and are continuing to pump water from affected premises. Staff from Veolia, working on our behalf, have begun to clean up some of the debris in the surrounding area.
“We are continuing to monitor the situation and will update you as it develops.”
Pictures taken outside Westminster Station after this morning’s incident show what appear to be hose reels lying on the ground.
Two tube workers can also be seen standing in front of the shuttered station.