The A3 southbound between the A272 Petersfield South and the junction with the A3(M) is closed after a vehicle collision.Vehicles are slowly being turned around by police and are being escorted back down the carriageway.A number of emergency services crews are at the scene of the incident.Fire crews from Southsea,Cosham are at the scene.
One of the two vehicles involved in the collision is overturned and is on it roof and the other is facing in the direction of oncoming traffic as it span out of control during the collision with the other vehicle involved.
Local diversion are in place whilst emergency service crews dealing the with the incident and carry out their investigation.
A spokesperson for Hampshire Police said the road is unlikely to be reopened before 6am.
More to follow shortly.