A bronze sculpture which was owned for 45 years by millionaire Exbury banker Leopold de Rothschild is set to fetch around £1m at auction.

The 7ft work, titled Curved Form (Bryher II) was produced by Dame Barbara Hepworth in 1961 and bought by Mr de Rothschild in 1967.

It is now expected to sell for between £1m and £1.5m at Christie’s in London tomorrow evening.

Christie’s confirmed: “Curved Form (Bryher II) stood until last year at Exbury Gardens in an alcove at the end of a terrace.”

The sculpture is named after Bryher, the smallest of the five inhabited islands of Scilly.

Christie’s say: “The soaring bronze of Curved Form (Bryher II) with its subtly modulated thickness and tapered basem Hepworth strung with copper wire. Using strings allowed Hepworth to introduce dynamic shapes into her work and to explore the relationship of the space between the forms.”

Hepworth herself explained: “The strings were the tension I felt between myself and the sea, the wind or the hills.”

Christie’s added: “Curved Form (Bryher II) is pierced with a large hole, an essential element in Hepworth’s sculpture from 1932 onwards. Hepworth used holes as a device for creating abstract form and space and to unite the front and the back of the work.”

Yorkshire-born Dame Barbara was 72 when she died in a fire at her studio in St Ives, Cornwall, on May 20, 1975.

Leopold de Rothschild, pictured left, was born on May 12, 1927, and was a great-great-grandson of Nathan Mayer Rothschild, who established the English branch of the family and the bank, in the early 19th century.

He was brought up mostly at Exbury House on the estate his father had acquired in 1918 and where his father created the 250-acre woodland garden.

Leopold de Rothschild, who died last year, gave generously to good causes and was once described as “an angel with revenue”.

In 1985, he was awarded a CBE for services to music and the arts.