The A343 road from Enham Arch up to the Roman Way roundabout is closed this afternoon following an incident.
None of the traffic lights on the Tesco Roundabout are working.
Emergency services are on the scene.
Hampshire Police have not confirmed what the exact nature of the incident is, but locals have reported hearing large bangs shortly before the road was closed.
Eye witnesses have suggested that a telegraph pole was on fire near to the arch itself.
Drivers and pedestrians are advised to avoid the area.
Update 17.05 – the road is open, but there are still delays.