A masterpiece by Francis Bacon has become the most valuable piece of artwork ever sold by auction house Christie's in Europe after going under the hammer for a record STG42.2 million ($A78.67 million).
The six-foot tall canvas of Bacon's former lover and muse George Dyer was due to fetch around STG28 million but the sale smashed the estimate after being bought by an anonymous buyer over the phone.
Dyer died of an overdose in Paris two days before the painting was displayed at Bacon's first major retrospective at the Grand Palais in 1971.
The piece, called George Dyer Talking, is the most significant large-scale portrait of Dyer to be offered at auction in more than a decade.
The most expensive of Bacon's work was his triptych of Lucian Freud, which sold for STG85.3 million at Christie's New York last November.
