6 July 2010 Last updated at 03:38 ET

Artefacts from Earl Spencer's Althorp estate auctioned

The Rubens painting could fetch up to £12m at the auction

Artefacts from the ancestral home of Diana, Princess of Wales, are expected to raise £20m when they are sold at auction over the next three days.

Among the items to be auctioned from Althorp House in Northamptonshire is a painting by baroque artist Sir Peter Paul Rubens.

The work, A Commander being Armed for Battle, was painted in about 1613-14 and could fetch up to £12m.

Althorp, the home of Earl Spencer, is undergoing a £10m restoration project.

The auction of artwork, English and French furniture and porcelain from the Spencer collection and treasures from Althorp's attics will fund reinvestment in Althorp and its estate.

The auctions are taking place at Christie's London sales rooms.