- 15 updates
Police have been criticised for not revealing more information about a "mysterious" flammable material that sparked an 11-hour closure of the M3.
Thousands of motorists were caught up in long queues when it was shut on Saturday between junctions nine and 11.
Some were trapped for more than eight hours and said more could have been done to keep them informed.
Rachel Hepworth spoke to some of those caught up in the chaos, and former Police and Crime Commissioner for Hampshire, Simon Hayes.
Thousands of motorists have been stranded for hours today after the M3 motorway was closed - by what police have described as "potentially hazardous material" in the carriageway.
The stretch between junctions nine and eleven near Winchester was sealed off shortly before four o'clock this morning. It has resulted in traffic chaos across a wide area of Hampshire, as Richard Slee reports.
Lucy Thomas has been stuck on the M3 for five hours.
Highways England is urging motorists around Winchester to plan ahead and leave extra time for their journeys as the northbound M3, for traffic travelling towards London, has now reopened between junctions 11 and 9 but traffic remains slow, and the southbound M3 remains closed.
The motorway was closed in both directions this morning after Hampshire Police were alerted to potential hazardous material just before 4am today, with traffic trapped within the closure released by 7am this morning.
Police and emergency services are continuing their investigations on the southbound carriageway, which remains closed between junctions 9 and 11. Southbound traffic continues to be diverted to follow the solid triangle symbol route.
Severe delays are anticipated in the area until at least 6pm. and drivers further afield are advised to use alternative routes if possible.
Latest ITV News reports
Witnesses sought after flammable- not explosive- material appears to have been thrown from motorway bridge on two consecutive weekends
Motoring groups are calling for better information for road users after thousands of motorists were trapped on the M3 in Hampshire.