John Constable's (1776-1837) "The Lock," one of six paintings that make up the artist’s most celebrated series of large scale works, will be offered at Christie's in London this summer.

Part of the series that includes "The Hay Wain," now in The National Gallery, London, "The Lock" is the last to remain in private hands. From the private collection of Baroness Carmen Thyssen Bornemisza, widow of Dutch-born industrialist and art collector Baron Hans Thyssen-Bornemisza, it has been sold only once since it was acquired from the artist.

When bought at auction in 1990 for £10.8 million, it became the most valuable British painting ever sold at the time – a record it held for 16 years.

The current auction record price for a British painting is $86.3 million for a 1976 Francis Bacon triptych sold in 2008

It is expected to bring between £20 million to £25 million ($30 million to $40 million) at Christie's Old Master & British Paintings Evening Auction on July 3.

"The Lock" was finished and exhibited at the Royal Academy in 1824, one of the most significant years in Constable’s career, which saw "The Hay Wain" exhibited at the Paris Salon and King Charles X of France award him a gold medal.

Constable wrote, "My Lock is now on my easil ... It looks most beautifully silvery, windy & delicious - it is all health - & the absence of everything stagnant, and is wonderfully got together after only this one year’." (Beckett, op. cit., VI, 1968, p. 200).