M3 traffic is building into long delays near Eastleigh after the southbound carriageway closed from Junction 12. Drivers were diverted off the motorway at the junction, and National Highways urged them to allow extra time or use alternative routes.
Junction 12 diversion
The closure is affecting the southbound side of the M3 at Junction 12, where traffic is being sent off the motorway. That leaves drivers on the approach facing slower-moving conditions as the diversion feeds vehicles away from the closed carriageway.
National Highways said police investigation works were ongoing on the route. That means the restriction is tied to active work at the scene rather than a routine hold-up, which is why the disruption is already building around the junction.
Hampshire and Isle of Wight Constabulary
The closure was linked to a police-led incident, but the nature of that incident has not been given. Hampshire and Isle of Wight Constabulary is the force named in the incident response, yet the available details stop at the fact that investigation work is under way.
For drivers, the practical step is straightforward: stay clear of the closed southbound section if possible, or build in extra time before reaching Junction 12. National Highways also advised motorists to seek alternative routes while the restriction remains in place.
Eastleigh route impact
The immediate impact falls on traffic heading southbound past Eastleigh, where the motorway closure is creating delays before vehicles reach the junction. The route is still open in the northbound direction, but the southbound side is the one under restriction.
What the scene does not yet provide is a reason to expect a quick return to normal flow. With investigation work still active and traffic being diverted off the motorway, the best option for anyone already en route is to leave extra time and avoid Junction 12 if another route is available.
