Sotheby's has announced a summer auction of what it describes as "the greatest collection of 20^th Century British art ever to come to the market".  The Evill/Frost Collection comprises some of the most important and influential British paintings and sculptures ever created.

The three-part sale, which commences on June 15, will include the single largest collection of Stanley Spencer paintings that have ever come up for auction, as well as work by leaders such as Henry Moore, Dame Barbara Hepworth and Lucian Freud - the grandson of psychologist Sigmund.

The collection was assembled by Wilfred Evill between 1925 and 1960, and maintained after his death by Honor Frost.  Consequently, the sale of these pieces is most likely a once in a lifetime opportunity for art lovers and investors to purchase a classic British masterpiece.

The major highlight of the sale is a Spencer piece, entitled Workmen in the House.  Painted in 1935, it is one of Spencer's most well-known and iconic creations, yet has hardly been seen in the flesh.

Stanley Spencer's Sunflower and Dog Worship - valued at £1.5m

Depicting the chaos and intrusion that the title suggests, the painting still maintains a warm and comforting quality - probably due to the fireplace at its centre.  This wonderful piece has an estimate of £1.5-2.5m; quite something for a British painting.

Collectors interested in Spencer's image of workmen and the home may also be intrigued by Kurelek's 'Roofers' piece, which will be auctioned by Heffel in late March.

Sotheby's will also be selling Spencer's bizarre yet joyful garden scene, Sunflower and Dog Worship.  Created in 1937, it was snapped up quickly by famous novelist and art collector Sir Hugh Walpole.  Evill purchased it seven years later for £100.  Sixty-seven years later, it has an estimate of £1-1.5m.

Other excellent pieces include Freud's Boy on a Sofa, which has a high estimate of £600,000, and a bronze rocking chair by Henry Moore - expected to realise between £800,000-1.2m.  The list of remarkable art works goes on and on - paying testament to the quality of the Evill-Frost collection.