Police have confirmed that the M3 is now open in both directions near Winchester,
It has been closed since 3.49am today when a suspected ‘hazardous substance’ was found on the carriageway, and the bomb squad was called to deal with it.
No details have been released about what the substance was or how it may have come to be on the road.
Long queues have developed across the area, with Winchester said to be gridlocked.
A police spokesman said: ‘We are now fully lifting the road closure on the M3.
‘We understand the inconvenience today’s closure has caused, but we thank you for your patience as we dealt with matters on the scene.’
Motorists reported being stuck for hours as a result of the ‘chaos’, while others risked injury by driving the wrong way down the hard shoulder.
Manchester United fan Paul Hibbert was travelling with his friends to see his team play Southampton but decided to leave the coach and make the one-and-a-half-mile journey to Winchester station by foot, walking along the hard shoulder to junction 9.
The 53-year-old, from Manchester, said: ‘People here are driving up the hard shoulder.
‘One of those idiots has hit a car that pulled out in front of him - it’s chaos.
‘We got the National Express at quarter past midnight to London and got the 8am bus to Southampton - it’s 1pm now.’
Social media users shared pictures of the scene, with one showing a man walking his dog on the hard shoulder, others playing golf, and another doing a handstand on the carriageway.