A footbridge collapsed Saturday onto the motorway linking London and Britain's closest ports to continental Europe on one of the busiest days of the year, though remarkably only one person was injured.

The bridge over the M20 in Kent, southeast England, came down after seemingly being hit by a truck, Kent police said.

The South East Coast Ambulance Service said a motorcyclist aged in the 50s had been taken to hospital with suspected broken ribs.

Pictures from the scene on social media showed half the bridge still hanging over the coast-bound side of the road.

Meanwhile on the London-bound side of the road, there was a truck carrying bulldozers on the hard shoulder, and the other half of the bridge came down on another truck that was overtaking it.

Eyewitness Sonny Gladdish told the BBC that the truck with the bulldozers had hit one leg of the bridge, causing it to collapse, while the motorcyclist saw the bridge coming down and threw themself off the bike.

It appears that the motorcyclist slid through a very narrow gap underneath the collapsed bridge.

Some motorists in the coast-bound direction took their chances and drove underneath the remaining half of the bridge, eyewitnesses told the BBC.

The motorway has been closed in both directions between the two nearest junctions.

Kent police had warned motorists Friday to expect a busy weekend as people return to Britain from holidays on continental Europe.

‘The last weekend of August is traditionally busy for the Port of Dover and Eurotunnel as people return to the UK after spending the summer on the continent,’ it said.