A pedestrian bridge has collapsed on the M20 motorway in Kent, crushing part of a lorry and injuring a motorcyclist passing underneath.
The road has been closed between junctions two and four as recovery work continues near Leybourne.
Witnesses said they felt "lucky to be alive" after the bridge came down shortly after noon on Saturday, in busy traffic at the start of the August bank holiday weekend.
Paramedics were seen treating one person at the scene, surrounded by rubble and twisted railings.
Photos showed shocked drivers getting out of their cars as long lines of traffic came to a standstill.
Andy Sunnucks said he felt "lucky to be alive" after falling debris hit the lorry and a motorcyclist who was passing underneath at the time.
“We came to a standstill and saw everyone running towards the wreckage,” he told The Independent. “We went to the wreckage and saw the lorry and the man underneath.
"He was physically under the bridge and wasn't moving. It really shook us up."
Writing on Twitter, Alex Magaisa said: “This bridge collapsed in front of us as I was driving on the M20 just moments ago. I just drove. No time to think. It was incredible. It could have fallen right on top of our car.”
Kent Police said officers were called at 12.07pm to reports of the collapse on the London-bound carriageway.
"It is believed a lorry collided with a pedestrian bridge which has collapsed onto the carriageway below," a spokesperson said.
"No people are believed to be trapped in the debris, however one person is believed to have suffered injuries, not reported to be life threatening at this time.
"Police are treating this as a major incident and the M20 has been closed in both directions to allow this incident to be dealt with. Traffic will be heavier than usual."
A spokesperson for the South East Coast Ambulance Service said paramedics were treating one patient and that the air ambulance were sent to the scene.
The motorcyclist, in his 50s, was taken by road ambulance to Tunbridge Wells Hospital with suspected broken ribs.
The M20 remains closed between junctions two and four in both directions. The M26 is also closed in both directions between the M25 and M20.
Highways England said the M20 closure would be in place for "some time" as police turn queuing traffic around.
