A man armed with a sword has been arrested a few hundred yards away from the West Hove branch of Sainsbury’s in Old Shoreham Road.
The man, who was held at about 10am, was described as dressed in body armour.
Sussex Police said: “A man has been detained following an incident in Portslade this morning (Sunday 14 June).
“Police received a report of a man in possession of a sword and wearing body armour close to the junction of Old Shoreham Road with Hangleton Road about 9.46am.
“Officers responded and the suspect was swiftly detained.
“He has been taken to hospital as a precaution.
“A small area of land has been cordoned off as police investigations continue.”
Superintendent Rachel Swinney said: “I’d like to reassure the community that this was an isolated incident and inquiries are ongoing to establish the full circumstances.
“Anyone with any information about the incident is asked to report it online or call 101, quoting serial 464 of 14/06.”