A major police operation is under way after a lorry hit a motorway bridge, causing it to collapse on one of the busiest travel days of the year.
A major incident was declared on the M20, the main route to the Channel Tunnel and the Port of Dover, with i mages on social media showing remains of the footbridge and damaged vehicles on the carriageway between junctions three and four.
Alex Magaisa was driving past the lorry involved just as the bridge collapsed, with his wife and two young sons in the car. They were on their way to Gatwick Airport to catch a flight to Belfast to see family for the bank holiday weekend.
The University of Kent lecturer, 41, said: "My instinct was just to drive through. My wife saw the bridge falling and there was a big noise. I had to manoeuvre through the debris.
"We stopped afterwards for about 30 minutes, and there was another car with a family behind us. Luckily no-one seemed to have been hurt.
"It was a big shock. It's only just starting to sink in now what might have happened. We were right in the line of fire and we could have been crushed."
Emergency services said a male motorcyclist aged in his 50s had been taken to hospital in Tunbridge Wells following the incident with suspected broken ribs. His injuries were not believed to be life-threatening.
An estimated 13 million drivers are expected to take to the road for a holiday or an outing between Friday and Monday, according to the AA.
The busiest single day for motorists embarking on leisure journeys is expected to be Saturday, when 10 million drivers have been predicted to be getting behind the wheel.
Andy Sunnucks, 24, who also saw the incident, said: "We were about 15 cars back on the same carriageway as the collision.
"It looked like a lorry had jackknifed, and I could see half the bridge was missing. We went to have a look and the back end of the lorry was in pieces."
The graphic designer, a passenger travelling from Maidstone to Sevenoaks, said: "The motorcyclist was laying down underneath his bike."
A Kent Police spokesman said: "It is believed a lorry collided with a pedestrian bridge which has collapsed on to the carriageway below.
"Officers are in attendance along with Kent Fire and Rescue Service and South East Coast Ambulance Service.
"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."
Highways England confirmed that the M26 in Kent had been closed eastbound between the M25 junction 25 and the M20 J3 to "assist management of traffic" following the incident. Its website advises drivers travelling clockwise on the M15 to Dover to continue on the M25 and use junction J2 to join the A2 and M2.