At 3.49am on Sunday (16 May), police responded to a report of a man claiming to be in possession of an explosive device and making threats outside Brighton Railway station.
The station was temporarily closed to the public and a cordon was set up as a safety precaution while officers carried out an extensive area search.
A 27-year-old man was swiftly detained and has been taken to custody for questioning.
He was not in possession of an explosive device.
An additional sweep of the area was carried out by armed officers.
Superintendent Justin Burtenshaw said: “This is being treated as an isolated incident and there is not thought to be any threat to public at this time.
“The cordon has now been lifted and train services have resumed from Brighton Railway Station.
“Officers remain at the scene working with British Transport Police to carry out further enquiries.
“We are thankful to the public for their patience and understanding while we carried out our work.”