East Croydon station has been evacuated along with nearby streets and buildings as police probe a “suspicious vehicle”.
Video and pictures show a huge police operation around the busy station which is one of the most popular for commuters heading into London.
Police deployed bomb disposal robot and witnesses have reported hearing a “loud bang”.
Trains, trams and buses have all been suspended around the area.
Witnesses have described the scenes as “madness” as hundreds of people spilled out of buildings and the station.
Met Police confirmed they were probing a “suspicious vehicle” in Dingwall Road.
Pictures show a silver Vauxhall Corsa parked on the pavement close to the station.
Dingwall Road runs alongside the transport hub and past the popular Boxpark.
The grey hatchback was reported to the cops at around 8.45am.
And the police are taking no chances amid the ongoing threat of terrorism in the UK.
Video shows the robot using its arm to open the door and remove items from the vehicle.
Once cops were satisfied it was safe, police officers could be seen inspecting the car up close.
Several bus routes were diverted as they were unable to stop at East Croydon.
People were urged to avoid the the town centre amid the incident which left the streets thronging with evacuated commuters and workers.
One witness said: “There is a suspicious vehicle on Dingwall Road outside the station parked in a really odd place and they're clearing the area.”
Another added: “Stabbing in broad daylightlast week at East Croydon and now a suspicious package and bomb squad here this week.”
And one said: “Forced to change at East Croydon today because all the usual trains are cancelled.
“Now we’ve been evacuated and are standing safely just outside the station.”
In a statement, British Transport Police said: "We are on scene in East Croydon as our colleagues at Met Police assess a suspicious vehicle in the area.
"The station has been closed and trains are not stopping there as a precaution. Thank you for your patience."
Another witness said: "East Croydon a bit of a mess. All closed off this morning because of a supposed bomb scare."
As of around 10.50am roads begun reopening around the station as train and tram services returned to normal.
In a statement, the Met Police have said the car is "non-suspicious".