A forgotten painting by LS Lowry has fetched more than £1m - twice the expected price.
The Salford artist's painting of Liverpool's famous Liver Building was bought in 1963 by Vernon's Pools founder Vernon Sangster.
It has been seen in public once, at Liverpool's Walker Art Gallery in 1973.
The Sangster family are selling the painting as well as two others by Lowry, at Christie's 20th Century British Art Sale in London on Friday.
The rediscovered work was estimated to fetch between £300,000 and £500,000, and is unusual because most of Lowry's landscapes were of Manchester and Salford.
An anonymous bidder paid £1,072,000 for the work.
All three paintings are from the collection of the late Robert Sangster, racehorse owner and son of Vernon Sangster.
A Christie's spokesman said: "This rediscovered masterpiece is one of the finest works by the artist ever to come to auction.
"LS Lowry's style saw him portray the townscapes created by the Industrial Revolution, often showing skylines of smoking chimneys and streets teeming with people.
"These landscapes were often composite images created partly in his imagination, but The Liver Building, Liverpool, steps away from this trend and offers a faithful view across the Mersey to the distinctive skyline of its eastern shore."
The other Lowry paintings up for auction are A Quarrel (1935), which portrays a street fight, and Procession In South Wales, Whit Monday (1963), showing a group of people dressed in their Sunday best.
Lowry, who was born in Stretford in 1887 and died in 1976, is most famous for his industrial matchstick men scenes.