A triptych of Lucian Freud by friend and fellow artist Francis Bacon sold for £23m at a Sotheby's London auction on Thursday.

The 14-inch high Three Studies for Portrait of Lucian Freud went for three times its pre-sale estimate in a furiously fought over lot that attracted 10 bidders across four continents. The successful buyer's identity is unknown.

The 1965 work has remained in a private collection for most of its existence and had previously been offered for private sale at £15.5 million.

The painting formed part of a 60 piece artwork sale from the private estate of Swiss collector George Kostalitz.

The 1965 work made three times its estimate

Bacon and Freud met in 1945 and depicted each other on a number of occasions.

"This striking painting has everything a collector in the current market is looking for," said Cheyenne Westphal, chairman of Contemporary Art Europe at Sotheby's.

"It is an artwork that radiates 'wall-power' with its brilliant colour and dramatic brushstrokes.

"It narrates one of the most impressive artistic relationships of the 20th century between two titans of British art and is desirably fresh to the market having remained in the same collection for almost half a century."

A record price for Salvador Dali

The same auction saw a 1929 Salvador Dali work, Portrait de Paul Eluard, more than double its pre-sale estimate.

Today, Dali's surrealist vision has been duplicated on millions of postersm although it is rare that his sought-after early works appear at auction. While their appearances are scarce, demand for early Dalis among collectors is clearly fervent - as proven by the work's final £13.5m price.

Every item of the £93.5m sale sold, ensuring it rose well above the £55m estimate - a reminder that investing in art can be a wonderfully surprising, and financially enriching, experience.

Not everyone can own a Bacon or a Freud but you don't necessarily need to remortgage your home to obtain works by leading artists.