London, March 30 (IANS) Princess Diana's brother, Earl Spencer, has decided to sell off his family treasures to collect up to 30 million pounds, a media report said.

Earl Spencer, who plans to marry for the third time, will increase his 100 million pounds fortune by clearing out the heirloom from the ancestral home in Northamptonshire and the Spencer House, the family home in St James's which is one of London's last remaining private palaces, Daily Express reported Tuesday.

The heirloom to be sold includes paintings, furniture, porcelain and horse-drawn carriages.

They are to be sold off in a series of auctions at Christie's in London. It includes an Old Master by Peter Paul Rubens that is likely to fetch between 8 million pounds and 12 million pounds.

Althorp estate was undergoing a 10 million pound restoration, and the trustees said they decided to sell items which were "not core" to the collection.

The Rubens picture, which was painted in 1613 or 1614, has been at Althorp for more than 200 years.

"This magnificent work by Rubens is one of the most important works by the artist to remain in private hands in the UK," Richard Knight, co-international head of old masters and 19th century art at Christie's, was quoted as saying.

"It is a museum quality masterpiece and will have wide international appeal."