The future of a popular off-road motorcycle site is under new threat after a quad biker was fatally injured as his distraught teenage daughter looked on.

Sales executive director Mark Clifford, 45, flipped his machine as he tried to ride up the face of a steep quarry.

He was airlifted to Airedale Hospital after the accident at Flappit, near Cullingworth, but he was pronounced dead a short time later.

The tragedy comes as Bradford Council seeks legal advice about the future of the popular common land site which off-road motorcyclists have used illegally for decades.

Mr Clifford, of Holroyd Mill Lane, Micklethwaite, had been trying to ride the Polaris 800cc quad bike up a steep bank when he lost traction, rolled backwards and flipped over.

His 17-year-old daughter, Floss, watched in horror as the accident unfolded in front of her on Saturday morning.

Motorcycle scrambler Jordan Byrne, 14, said: "He almost got to the top. He could not make it so he stopped and the quad started rolling back down. He tipped his back brake when he got near the bottom and the quad flipped and landed on him. I saw it roll twice.

"I ran over to see if he was OK. The guy was lying on his back with blood over his face."

Jordan ran to get help from his father Kevin, 47, who was sat in a nearby car park.

Mr Byrne, of Undercliffe, said: "The lad was laid down at the bottom of the hill and I could see blood from his nose and mouth. I shouted down to the lad who was looking after him.

"He shouted back that he had stopped breathing but he had done CPR and got him going again."

Mr Clifford was a keen participant in extreme marathons from which he raised tens of thousands of pounds for charity.

He had competed in the Marathon des Sables in the Sahara Desert, the Kilimanjaro Marathon and the highest marathon in the world - the Everest Marathon.

Last year, he raised £40,000 for abandoned and orphaned children in Eastern Europe and Africa by completing the North Pole Marathon.

His wife Debbie was too distraught to speak as West Yorkshire police and the Health and Safety Executive - which has already raised concerns about the safety of the site - investigated his death.

The controversial site, alongside the A629 between Denholme and Keighley, has been a Mecca for scrambling enthusiasts for more than half a century.

Motorcyclists who use it have called for the quarry to be turned into an official site but the council is seeking legal advice about its continued illegal usage amid safety concerns.

The authority is also considering closing a large lay-by used by motorcycle owners to park their vehicles and double-yellow lines could also be placed on the A629 giving police power to stop scramblers parking their transportation on the road.

It is understood an urgent meeting with council lawyers will be held after the Easter break as a result of Saturday's accident.

Despite the tragedy the quarry was full of scramblers and quad bikers within hours of the accident.

Mr Byrne said: "It's what my son loves. It's his thing and he looks forward to it all week.

"Generally it's a really good set of lads who come up here. Everyone looks out for each other. Accidents will happen but there are more lads killed on the roads on bikes."

Councillor Michael Ellis (Con, Bingley Rural) said it would not be legally possible to turn the quarry into a designated off-road site.

He said: "I have always supported an off-road facility, be it at the Flappit or anywhere else. But legally that particular area cannot be used, I am told, because it's common land and it's against the law to drive motor vehicles on common land."

Councillor Michael Walls (Con, Queensbury) said he expected the issue to be discussed at a meeting of the Environment and Waste Management Improvement Committee on Wednesday.

Anyone with information about Mr Clifford's death should contact PC Richard Hirst, of Keighley police, on 01535 617059.