Media playback is unsupported on your device Media caption Motorist Mike Partridge describes how he bought an ice-cream and chatted to other stranded travellers

A man has been arrested after the M25 Dartford Crossing between Kent and Essex was closed in a security alert.

Drivers were stuck for more than seven hours in nine-mile tailbacks after a pedestrian, who was spotted behaving strangely, was held.

The Queen Elizabeth II Bridge and both tunnels were shut when Kent Police said officers found a suspicious item.

But after Army bomb disposal teams investigated, they said the item posed no threat and reopened all routes.

'Man was shouting'

The A20 was also closed in Dover as officers stopped a coach as part of their inquiries into the Dartford Crossing incident.

The coach was removed from the scene, police said, and the road was later reopened. No further arrests were made.

Image caption The toll booths at the Dartford Crossing were cleared of vehicles

Motorists stuck in queues on the crossing said an Army bomb disposal vehicle, ambulances and emergency service vehicles attended the scene.

Graeme Brouder, 36, from Twickenham in south-west London, said: "I was coming off the other side of the bridge towards the tolls at about 16:30 BST on Friday.

"I was about five cars from the barrier and I saw a guy out of the corner of my eye come running along the side of my car, he ran to the barriers.

"He came back towards the cars, he went across into the lane next to me, tried to get in the car next to me, he was shouting something - I had my windows up so I couldn't hear him.

"He was shouting at that car, tried to get in that car, ran past mine, tried my door handle, and then ran down the lane behind me and he was just shouting at everyone.

"He was running around, he was trying to get in everybody's cars."

Trapped vehicles

Traffic trapped on the bridge was eventually released and diverted back into Essex, while some trapped vehicles were released from the tunnels on Friday night.

The toll booths were also cleared of traffic.

Tailbacks stretched through Kent, on the anti-clockwise M25, and in Essex, on the clockwise stretch.

In London, there were severe delays in East Ham, Beckton, Bow, Woolwich, at the Blackwall Tunnel and all approaches to the M25.

The A11, A12 and A13 also experienced heavy traffic.

The A282 Dartford to Thurrock crossing over the River Thames, which consists of the Queen Elizabeth II Bridge and two tunnels, is used by 140,000 vehicles a day.

Traffic heading south into Kent uses the bridge, while northbound vehicles travelling to Essex use the tunnels, with the M25 linking up either side.