The oil painting, an atmospheric depiction of Mousehole harbour in Cornwall by British artist George Hammond Steel, was donated to the RSPCA shop on High Street in Wootton Bassett, Swindon.
After being identified as a quality piece, it was brought to neighbouring RWB Auctions shortly before Christmas for valuation.
Kelly Ohrland, senior auction administrator at RWB Auctions, said: “This is exactly the kind of result we love to see.
“We work closely with charity shops and local organisations to help them realise the full value of special items, and this painting is a perfect example of what can happen when the right piece meets the right audience.
“The level of competition on the day was thrilling.”
The undated oil painting by George Hammond Steel of Mousehole harbour. (Image: RWB Auctions)
The painting was given a conservative estimate of £600 to £800 but attracted intense interest during RWB Auctions’ Antiques and Interiors sale on January 14.
It eventually sold for £3,900 to a private collector in Nottinghamshire.
Gordon Brockman, the auctioneer who first assessed the painting, said: “From the moment I saw it, it was clear this was a strong and confident work by George Hammond Steel.
“While estimates must always be realistic, it is immensely satisfying to see collectors respond so positively and to know the proceeds are going to such a good cause.”
Describing the painting, which is rendered in oils, the auction house said: “The work depicts a low tide from the harbour walls, with small boats in the foreground and charming seaside cottages above.
“It might be a study for a larger painting of the same scene, which last sold in 2019 for £4,940.
“The white building with five windows in the centre of the picture is today the Mousehole Deli & Kitchen.”
The painting was signed “HAMMOND STEEL” in the lower right-hand corner.
The proceeds have been donated to the RSPCA.
According to RWB Auctions, George Hammond Steel was a British painter and stained-glass designer, best known for paintings of Cornish towns and Derbyshire landscapes.
Born in 1900, he spent much of his life living in Ashdon, Kent, before his death in 1960.