A portrait by Francis Bacon of his lover George Dyer has sold for £42.1m ($70m) at Christie's February 13 post-war and contemporary art auction in London.

The work achieved an increase of 40.6% on its £30m ($49.2m) estimate, setting a new record at auction for a single canvas by the artist.  

The painting is now the most valuable single canvas by Bacon ever sold at auction

The painting dates to 1966 and pictures Dyer on a stool. Dyer was a violent and forceful personality, and one of Bacon's foremost creative influences.

Francis Outred, head of post-war and contemporary art at Christie's Europe, commented prior to the sale: "Francis Bacon's position at the forefront of 20th century painting was highlighted at Christie's in November when his triptych of Lucian Freud sold for $142 million and became the most valuable work of art sold at auction.

"For the triptych we had six collectors who bid at over $100 million, showing both the global demand which we see in today's art market as well as the huge appeal of the artist."

This latest sale serves to highlight Bacon's position at the forefront of 20th century art.

An Abstraktes Bild painting by Gerhard Richter was another highlight, achieving £19.5m ($32.4m).

The lot becomes the third most valuable work by Richter to have sold at auction - pushing Wand, which sold for £17.4m ($28.7m) at Sotheby's London on February 12, into fourth place.

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