A sheep farmer has criticised "selfish" off-road bike riders who he claims are wrecking his livelihood.

Simon Tidswell, who owns Sand Beds and Whinny Hill farms, near Denholme, said trials bikers had caused thousands of pounds of damage to his property.

He said they had repeatedly cut through wire fencing separating the quarry, known as "The Flappit", from Black Moor and Hallas Rough Park, where he grazes hundreds of sheep.

He added they had also cut the fencing running along the nearby Halifax Road.

He said: "These aren't just small holes - these are great big gaps which sheep can easily get through.

"It's only a matter of time before one of them gets on to the road in front of a car. I now have to walk the fence perimeter every weekend. In the past 12 months I've spent £6,000 on new fencing, only to have it cut again.

"The people doing this are actually coming along with wire cutters. They're completely selfish and it's a minority spoiling things for the majority."

He added he had recently discovered £2,000 worth of damage to his fences.

He said those responsible were doing it in order to ride on Black Moor and Hallas Rough Park, even though this land was not open to the public.

He said when he confronted four trespassing bikers earlier this month he was sworn at and threatened.

"Now it's happening in lambing season the stress caused by the bikes is making the sheep abort. It's also devastating the moorland itself," he added.

Mr Tidswell, 41, said his family had grazed livestock on the land for three generations.

Mick Sugden, 36, who has ridden trials bikes at the quarry for four years, said he and his fellow enthusiasts struggled to find places where they could pursue their hobby without trespassing.

But the Silsden resident added this was no excuse for damaging farmers' property.

Barry Snow, the company secretary of Dennis Gillson and Son - which owns Black Moor and Hallas Rough Park - said the firm was aware that some bikers were trespassing on the land.

He said: "This has been going on for some time. They're definitely not allowed to be there but they're hard to stop."

A spokesman for West Yorkshire Police confirmed officers had been informed of the trespassing and the damage and were investigating the incidents.