LONDON (BLOOMBERG).- Francis Bacon works discovered on the backs of amateur paintings sold for almost $70,000 today at an auction in Surrey, southern England.

The six works, showing background and architectural elements from what appear to be 1950s “Pope” paintings by Bacon, were on the reverse of canvases by the little-known artist Lewis Todd offered by Ewbank’s on the second day of a sale in Guildford.

A top price of 27,544 pounds ($41,000) with fees was paid by a telephone bidder for a fragment showing the leg of a chair and a glimpse of ecclesiastical clothing. Concealed beneath a 1958 studio interior by Todd, it had been estimated at 25,000 pounds to 35,000 pounds, based on hammer prices. Three Bacons were successful, selling for a total of 44,822 pounds.

Some blue background brushstrokes by Bacon fetched a further 11,268 pounds, again just more than the low estimate. The group had been valued at as much as 145,000 pounds.

Todd, who died in 2006 at the age of 81, was a caricaturist for the Cambridge Daily News. After World War II, he was encouraged to paint by the local artists’ suppliers Heffer, who also provided materials for Bacon.

Bacon favored painting on the unprimed reverse of canvases. Heffer provided rejected examples to Todd, who was asked to cut them up and then painted his own impressionist compositions on the unused fronts, the auction house said.

Five of the works were confirmed by the Francis Bacon Authentication Committee. Paint samples were analyzed by Northumbria University and conform to those used by the artist in the 1950s and 1960s.

In 2007, Ewbank’s sold a group of rejected and damaged Bacon paintings retrieved from a skip outside the artist’s London studio by electrician Mac Robertson. Valued at about 50,000 pounds, that collection sold for 1.1 million pounds.