Thousands of motorists were caught up in tailbacks last night as they tried to leave a huge motorbike event in Hampshire.

More than 40,000 people attended the MotoCross of Nations, described as 'the Olympics of MotoCross', near Winchester.

But as they tried to leave the event at Matterley Basin, near Cheesefoot Head, many were caught in queues for as long as three to four hours.

Part of the problem was caused by motorists who did not want to park at the venue left their cars by the side of the main roads leading to Matterley Basin and walked.

But the abandoned cars caused traffic chaos along the A31 and A272 at the end of the event.

Abigail Brimfield from the nearby Percy Hobbs pub said: "The roads are awful. People have been abandoning their cars on the side of the road for miles around.

"We had people arriving at our car park from 7am."

Police closed part of the A272 for several hours from about 4pm to allow traffic to exit the site, as previously agreed with organisers.

AA and RAC breakdown teams were put on standby as many motorists had forgot to turn off their lights, a police spokesman said.

Motorists were warned to stay away from the area.

Ros Kelly, a spokesman for the organisers Bike it Promotions said there had been ample parking on site for spectators.

"People didn't want to queue so they just parked up on verges and walked up. It was people being lazy," she said.

Earlier, a serious accident between a pedestrian and a lorry on the A31 near the Percy Hobbs pub caused tailbacks for those arriving at the site yesterday morning.

The pedestrian was taken to Royal Hampshire County Hospital with "critical" injuries, an ambulance spokesman said.

Meanwhile, police reinforcements had to be called to the final day of the event after trouble broke out on Saturday night, which led to about eight arrests.

A police spokesman said: "We received a call about a public disorder offence and we made some arrests on arrival as a result.

"We had reinforced policing in place the following day which is usual after a high-spirited Saturday night where there is a large number of people."