The identity of the victorious bidder at Christie's, London, has not been made public. The painting had been expected to fetch £24m.

Painted in 1919 in Giverny in France it has been seen in public just once in the past 80 years.

Monet's 1873 Le Pont du chemin de fer a Argenteuil, which sold in May, had held the previous record of £20.9m.

Experts say the art market remains in a "robust" position.

BBC arts correspondent David Sillito says that buyers from all over the world attended the sale.

The "hammer price" for the painting was £36.5m but the overall price rose to over £40m with taxes.

"There's never been such a picture sold at auction in Europe in the last 20 years," Oliver Camu of Christie's said.
Monet painted several smaller water lily pieces, sometimes referred to as his "water landscapes", before he decided to embark upon a series of large-scale Nympheas in 1914.

These paintings would eventually lead to his Grandes Decorations, the celebrated frieze now in the Musee de l'Orangerie in Paris.

Le Bassin Aux Nympheas is one of a tiny handful of paintings the artist relinquished during his lifetime as he viewed his water lilies as a large work in progress.

Of its three fellow paintings one is in the collection of New York's Metropolitan Museum of Art, another was cut into two and the third is in a private collection.

Other highlights in the sale included works from Pablo Picasso, Henri Matisse, Henri de Toulouse-Lautrec and Edgar Degas.

According to findings from the Hiscox-Art Market Research, 19th Century European art has seen a 13% rise in value since March 2007.

Art expert Charles Dupplin said: "It does seem that the art market is remaining reasonably robust, with some specific segments - such as 19th-Century European art - even undergoing a form of renaissance."

BBC