Mystery bidder who brought home the Bacon for £26million

The casually-dressed agent had to be pointed out to the auctioneer in the overcrowded salesroom at Christie's before he bought Triptych 1974-77.

It was the biggest bid of the auction as more than £73 million worth of art was sold.

The triptych, previously held in a private collection, was the last work in the series that Bacon painted after the suicide of his lover George Dyer in 1971. It sold to the anonymous buyer for £26,340,500, including auction fees.

It made it the most expensive work of art ever sold at Christie's in London and the most valuable post-war and contemporary work sold in Europe.

But it fell £150,000 short of the record for an auction sale of any Irish or British work set last May by another Bacon.

Christie's was packed, with dozens more watching on screens in overflow rooms with feverish bidding for certain lots while 17 of the 54 works on offer went unsold. But the Bacon triptych was the star attraction and it came down to two bidders in the room. One was an American, young and casually dressed - by the standards of auction rooms - in a brown corduroy jacket who spent much of the sale on the telephone until lot 35 came up.

Leaning against the door in a crowd of standing onlookers, he could not be seen by Jussi Pylkkanen, president of Christie's Europe and auctioneer, until a shout flagged him up.

He quickly secured the work. He refused to disclose the identity of the buyer but said of the painting: "It's beautiful, isn't it?" Christie's said the bidder was an agent for someone known to them but refused to disclose more details.

Total sales reached £73 million - the second highest total for a postwar and contemporary art sale - and saw artist record prices established for Gerhard Richter, Lucio Fontana and Bridget Riley.

Pilar Ordovas, head of post-war and contemporary art, said: "We saw active participation from American clients who bid competitively alongside other internationalcollectors. Christie's again established very strong prices for works of the highest quality, demonstrating the continued strength of the market."

It followed a record-breaking night at Sotheby's on Tuesday which saw the auction house sell paintings worth more than £115 million.

Sotheby's is expecting its Bacon painting, Study Of A Nude With Figure In A Mirror, painted in 1969, to sell for more than £25 million on 27 February.