The Earl of Cardigan has failed in a Court of Appeal battle over the sale of the ancestral home on the edge of Marlborough, which has been in the family for nearly 200 years.

Three appeal judges have approved the present trustee's plans to sell Tottenham House, a 100-room mansion in the 4,500-acre Savernake Estate for £11.5 million.

Lord Justice Moore-Bick, Lady Justice Black and Lord Justice Vos unanimously agreed to dismiss Lord Cardigan's objections.

Lord Justice Vos said Tottenham House was decaying fast and had been unoccupied since the 1990s and "everyone now agrees it must be sold - what is in dispute is the process by which the sale should be achieved".

The judge said the trustees of the Savernake Estate were seeking approval "for their momentous decision" to sell Tottenham House to an unnamed buyer, referred to as Mr A, for GBP11.25 million under a conditional contract dated August 19 2013.

The trustees were of the view that the intended sale price "is a good one that represents an opportunity not to be missed".

Lord Cardigan regarded the price as "inadequate" and the result of an ineffective and inadequate marketing exercise. He had taken legal action to have the trustees removed "broadly on the grounds that they are unfit to act".

Dismissing appeals by Lord Cardigan, Lord Justice Vos said judges who had heard two linked High Court cases over the dispute "were right to conclude that the trustees had shown that their decision to enter into and complete the intended sale to Mr A was one which reasonable trustees could properly take in the interests of the beneficiaries".

The main beneficiaries of the trust, said the judge, are the Earl and his son, Lord Savernake.