The National Trust is standing by its controversial decision to split up High Yewdale Farm despite outrage from both in and outside of the farming community.

High Yewdale, near Coniston, was left to the trust by children's author Beatrix Potter on her death in 1943.

The farm's present tenants, Jonny Birkett and his wife Ruth, have been farming the land for 35 years but six weeks ago Mr Birkett, 71, was told by National Trust members that the farm is to be split upon his retirement in October between four neighbouring farms and the flock given to another farm.

Mr Birkett's father, Robert, was selected by the famous writer in 1940 to take on the farm because of his excellent reputation as a shepherd.

The couple have been left distraught and their neighbours fuming but the National Trust says that it will to stick to its guns.

Mr and Mrs Birkett who have received dozens of letters of support and pledges from National Trust members that they will withdraw their membership if the split goes ahead fear that the quality of the land will decline because there will be too much for the other farmers to manage.

"I am really mad with the decision, it was made in an office before they told us," said Mr Birkett.

"We may be tenants but our family has looked after the land as though it was our own for over 60 years.

"Farming knowledge is something that is passed on from generation to generation, it's not something that you can learn at a university. These people (from the National Trust) have never dug a ditch or built a wall."

Mr Birkett also fears for the fate of his hefted Herdwick flock, descended from Beatrix Potter's own sheep.

Over generations of grazing on the same land the flock has developed a homing instinct, which means that they do not stray from their pastures.

But if the flock is moved onto another farmer's land, Mr Birkett believes that the sheep will become disorientated.

"It is the hefting system that needs protecting at all costs," he said.

But National Trust area manager John Darlington said that he would not go back on the decision to split up the farm.

He said that because of changes in the subsidy system the farm was no longer viable to be rented out to a single farmer. High Yewdale would benefit the other farmers by allowing them to attract more subsidy.

The decision had been made following long consultations with various groups including the farming community, he said.

"To stay the same is not an option there are major changes in agricultural subsidy which was going to have a major impact," he said.

"We would have expected this decision to have raised some concern but we have thought a lot about the best way forward for the farm."