Police say they were forced to shut down a motorsport event today after one rider died and another seriously injured in separate accidents.
Durham Constabulary said it closed down the quad and motocross event being held on land next to Low Hardwick Farm, and near Hardwick Hall Hotel, near Sedgefield, County Durham.
It follows the death of one rider in a collision and another which left another seriously injured in two separate incidents.
The first incident happened shortly after 1pm today and involved a man who came off his bike and suffered critical injuries.
He was taken by the Great North Air Ambulance to the James Cook Hospital in Middlesbrough, but was confirmed dead shortly after arrival.
A second rider was then hurt in a separate incident, which happened just before 2.10pm.
The woman rider, thought to be in her early 30s, was also taken by air ambulance to the James Cook with what are believed to be serious injuries.
Police took the decision on safety grounds to close down the privately-run event, which involved around 100 participants and 300 spectators.
Superintendent Mick Bird said: “We understand the formal investigation is likely to be led by the local authority, but we are carrying out initial inquiries into the circumstances.
"With two very serious incidents within little more than an hour, we felt there was little choice but to bring the event to a close.”
The investigation is not being led by Health and Safety Executive, as the incidents did not happen in a location which comes under their remit.