LATEST: The M3 has reopened in both directions.
Thousands of drivers have been stranded on a section of the M3 due to reports of a “potential hazardous material”.
Police were alerted in the early hours of Saturday morning and a bomb disposal team is on the scene currently.
The M3 is partially closed between junctions nine and 11 at Winchester and people have been advised to find alternative routes.
The eastbound carriageway was opened at around 1.40pm.
Pictures from the scene show a robot attending what appears to be a package.
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, told the Press Association: “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.”
Hampshire Police said: “Police were called at 3.49am to reports of potential hazardous material in the road.
“Our officers are working alongside partners from Hampshire Fire and Rescue Service and the Explosive Ordnance Disposal (EOD) team to establish exactly what it is.
“Nobody has been hurt in the incident.
“The road is still closed at this time, and we will endeavour to get the material cleared as soon as possible.”
Witness Jenna Keating, 31, a writer from Windsor, told the Press Association: “There are lots of people stranded here, people have got out of their cars to stretch their legs and things, but some are just turning round and going back down the hard shoulder.
“We actually spoke to police about this to see whether this was something we could do in the circumstances and they said ‘absolutely not’.
“They also said the delay had been quite well advertised, although none of the four of us in the car saw anything until we were in it.
“We’re one of the lucky ones, we’ve only been here for 40 minutes although we’ve basically only crawled forward into space probably left by those who are trying to turn around.
“I can’t think it’s a good idea to use the hard shoulder – there have been a couple of unmarked vehicles with sirens blaring coming up and using it, so it’s pretty dangerous if there are cars coming in the other direction.”
A spokesman for Hampshire Constabulary added: “We will endeavour to get the material cleared as soon as possible.”