Passengers were evacuated from London Bridge station after a man was spotted behaving suspiciously on a train from St Albans.
Officers were called at around 6.30pm on Monday and a full search of the train and platform were carried out as a precaution by the British Transport Police.
The BTP confirmed that no one matching the description was found and officers were satisfied there is no risk to the public.
Police CCTV enquiries are ongoing, the force added.
The search comes amid calls for tighter security on Britain’s railways after 10 people were stabbed in a terrifying knife attack on an LNER train from Doncaster to London on Saturday.
Anthony Williams was charged with 10 counts of attempted murder. The 32-year-old was also charged with another count of attempted murder and possession of a bladed article in connection with an incident at Pontoon Dock DLR station in the early hours of the same day.
Footage shared on social media appeared to show armed police officers making their way towards a platform at London Bridge station on Monday evening.
At London Bridge earlier on platform 4/5. All cleared now. Not sure what it was. pic.twitter.com/xQbciyHFip
— Lewis Cowan (@LewisCowan1997) November 3, 2025
Thameslink confirmed shortly before 7pm on X that police had been dealing with an incident at the busy London station.
“This has recently happened and we are working on gathering more information for you," the rail operator said.
Southern Rail said: "If you are travelling to or from London Bridge, you may need to use an alternative route to reach your destination."
Around 15 minutes after the warnings were put out the rail operators confirmed passengers were able to safely use the station again, but trains could be delayed as a result of the incident.
Witnesses described large numbers of people outside the station and being held at barriers as police swarmed the scene.
One user on X described people running on two of the station platforms.
Something going on at London Bridge. Lots of police and people leaving in hurry from platform 6/7.#londonbridge pic.twitter.com/6Wxl3KqAjp
— Harvey (@McCartneyHarvey) November 3, 2025
National Rail said passengers could expect delays until 8pm as a result of the incident.
In a statement, it said: “The earlier incident that the police were dealing with at London Bridge has now been resolved. Whilst service recovers, Thameslink services travelling through London Bridge may still be delayed or revised.”
A British Transport Police spokesperson said: “The train was stopped at London Bridge while officers carried out a full search of the train and platform as a precaution. No one matching the description was found and while officers are satisfied there is no risk to the public, CCTV enquiries are ongoing.”
