Hidden art by Picasso, Renoir and Matisse on sale

Masterpieces by Picasso, Renoir and Matisse unseen for decades are among the highlights of sales in London next month.

Record prices last year have encouraged owners to put works back on the market, confident they are likely to do even better this time.

Jussi Pylkkänen, president of Christie's Europe, said: "There is a masterpiece market — a Medici market — with significant collectors who have a huge appetite to buy the best. It is something I've never seen in the 20 years I've been working."

There were few signs of "distress sales" by owners urgently raising cash, he added.

A French collector has consigned a group of four works owned for 60 years, including Mademoiselle Grimprel Au Ruban Rouge by Pierre-Auguste Renoir, with an estimate of up to £2.5 million. Another is selling Pablo Picasso's portrait of his second wife, Tête De Femme (Jacqueline), for an estimated £3 million-£4 million. It has not been seen in public since 1967.

Nu Aux Jambes Croisées, by Henri Matisse, is up for auction for the first time having been in a Swiss collection since 1963. It dates from 1936 when Matisse was beginning an intense relationship with model and muse Lydia Delektorskaya. The estimate is up to £4 million.

The sales also include modern works such as a group from the Sixties inspired by the Space Age. It is led by a rare "gold sponge relief" — a sponge fixed with resin and painted gold — by Yves Klein.

Highlights are at Christie's in King Street, St James's, from today. The Impressionist and modern art sale is on 2 February and post-war and contemporary on 11 February.