Properties around Nightingale and Dyer Road in Shirley are being evacuated after the discovery of an old shell.
Builders had been in the process of conducting ground works when they discovered an old ammunition shell at around 1pm. It has been described as 2.5ins in diameter and has a rusty 22-inch brass bottomed shell. Up to 50 properties have been evacuated.
A 50-metre cordon has been placed around the shell, including roads and gardens.
Police are advising people to avoid the area. People already near the site are being evacuated. Those who do not wish to leave are being advised to stay indoors in a room which is furthest from the shell.
Bomb disposal experts are on their way to the site from Portsmouth.
The Wessex Scene will follow this incident as it develops.
UPDATE: The EOD have removed the shell. The cordon is being lifted.