Wiltshire Police are appealing for witnesses after a man was threatened by another man in a supermarket car park.
A police spokesperson said, "The incident happened at approximately 1.15 pm back on June 9 in Tesco Express Car Park in Wilton Road.
"An 18-year-old man was threatened by a man carrying a knife.
"A man in his 30s from Southampton has been arrested on suspicion of affray and possession of an offensive weapon and has been released on conditional bail while enquiries continue.
"We are keen to hear from anyone who witnessed the incident.
"If you can help, please call 101 and quote crime reference number 54230060454.
"Alternatively, call CrimeStoppers anonymously on 0800 555 111."