A series of 17th Century Spanish masterpieces may not be allowed to move from their North-East home because of planning laws.

Council chiefs believe the Zurburan paintings at Auckland Castle, Bishop Auckland, County Durham, could have listed building protection.

Church commissioners want to sell the 13 paintings, of Jacob and his 12 sons by Francisco de Zurburan, to raise money for cash-strapped dioceses and parishes. But because the Long Gallery where they are hung was refurbished to accommodate the paintings, it could prove difficult to remove them.

Auckland Castle, which is the home of the Bishop of Durham, is a Grade I-listed building.

Planning laws state that permanent fixtures and fittings that are part of the historical and architectural character of a building carry the grading, and therefore the same protection, as the building.

Last week, it was reported that the Bowes Museum, in Barnard Castle, might buy the paintings and keep them at Auckland Castle, which would be used as an education centre.

A meeting of Durham County Council's cabinet yesterday agreed to take part in discussions about these plans.

The council's chief executive Kingsley Smith raised the question of the paintings being listed.

He said: "It may well be that these particular pictures could be listed and could not be removed from the castle.

"The pictures could be preserved in County Durham without costing anyone a penny."

A spokesman for the county council said: "We believe it is quite possible that the Zurburan paintings in Auckland Castle fall within this category. We are working with Wear Valley District Council, which is the local planning authority, to determine whether this is the case.

"If it is, any attempt by the Church Commissioners to remove the paintings, for instance, to sell them to a new owner, would need listed building consent and could prompt formal objections from any interested party as part of the planning process."

A spokesman for the church commissioners said: "We are not in a position to discuss any details relating to the sale of the Zurburans."