A TALENTED border collie is in the field rounding up her flock today completely unaware of her status as Britain's most expensive sheepdog.

Cass the collie has become the most valuable working dog to be sold at auction after fetching £3,300 at a North Yorkshire market.

Farmer Paul Evans, 37, offered the highest bid for one-year-old Cass - whose full name is Lynwood Cassie - following fierce bidding at Skipton.

"I knew immediately that Cass was the one I wanted. Everything was so natural about her and she was also very pretty, a mottled black, white and tan," he said.

Convinced that she will go on to be a hit at sheepdog trials, Mr Evans, of Great Howle Farm, near Ross-on-Wye, has had her kennel fitted out with cameras and alarms to deter envious competitors.

Jeremy Eaton, the auctioneer who sold Cass, said good dogs regularly sell for between £1,500 and £2,500 but Cass was the first dog to be auctioned for more than £3,000.

He said it was her skilful handling of the sheep at such a young age that attracted such a bidding frenzy at the auction, which attracted about 2,000 farmers and enthusiasts.

"To have a dog perform a trial like that at that age is quite exceptional. It requires people to spend an awful lot of time to get dogs to that level," he said.

"She can already out-perform older dogs."