Fenchurch Street Station was evacuated during rush hour this evening, disrupting hundreds of commuters' journeys from the central London terminus.
British Transport Police officers were called to the station at 6.37pm "following reports of a robbery on board a train".
Armed police then evacuated the station and carried out a full search of the train, which had been travelling to Fenchurch Street from Southend Central, for the man who had reportedly had a knife.
No one matching his description was found.
C2c Rail, which manages Fenchurch Street Station, said later on this evening it was still processing delays to its services following the evacuation.
Fenchurch St Station is currently reopened safely and services are back up and running with some amended: https://t.co/ZTbViTNj77— c2c Rail (@c2c_Rail) August 2, 2016
Apologies for the current delays. Fenchurch St station is now opened. Services affected can be found here: https://t.co/bxu9p8mq2E— c2c Rail (@c2c_Rail) August 2, 2016
Last year almost 17.6m travellers used Fenchurch Street station. It mainly serves East London and south Essex.