Shortly after 1.14pm today, officers from British Transport Police received a report of a suspicious man on board a Southeastern train heading to London St Pancras.
Specialist teams from BTP, including firearms officers, were deployed to the scene to conduct a search. Just after 2.15pm a man was then stopped outside St Pancras station. A partial closure of station was put in place whilst teams carried out a search.
No weapons or suspicious items were found during the search. The detained man has been released with no further action.
The cordons have since been lifted and passengers have been allowed back into the station.