A JMW Turner painting of Chepstow Castle overlooking the River Wye has sold at auction to Chepstow Museum for £93,375.

The sale price has beaten by almost double the pre-auction estimate of £30,000 to £50,000.

The British artist was 19 years old when he created the watercolour, which has been kept in a private family collection in London since 1956.

The artwork is signed ‘Turner’ and dated 1794, with the attribution confirmed by leading Turner scholar Andrew Wilton.

It was sold at auction at Cheffins in Cambridge as part of The Fine Sale this month.

Patricia Cross, an associate at Cheffins, said: “Turner is considered one of the greatest landscape painters in the world, and this is an important collectors’ piece, offering a glimpse into his style in the early part of his career.

“With this in mind, we saw bidders from across the world join us both in the saleroom and online as the painting went to the auction block.

“As an important record of Turner’s early style which was developing at a quick pace at this time of life, the painting was offered in immaculate condition, having been held in a private London home since the 1950s.

“It has likely remained in the same family since it was last offered on the open market in 1917.

“Given its large scale and highly finished composition, we believe that it probably was painted as a presentation piece for one of Turner’s important patrons.

“We are delighted to have sold it to Chepstow Museum.”

JMW Turner died in 1851 aged 76.

The painting, which was offered on the open market for the first time in nearly 100 years, is one of only two Turner paintings of this view of Chepstow Castle and bridge in Monmouthshire known to be in existence.

The other is currently held in the Courtauld Institute of Art.

The painting depicts Chepstow Castle overlooking the River Wye, showing the view from downstream of a wooden bridge, complete with a boat in the foreground and the castle, alongside a series of cottages.

The version held at the Courtauld Institute is undated, less finished and smaller than the painting offered by Cheffins, according to the auctioneers.

Differences can be observed in the arrangement of the boats, the detailing of the town and castle and the position of the figures on the bridge.

Sara Burch, Monmouthshire County Council’s cabinet member for inclusive and Active Communities, said: “It’s fantastic news that the painting will be coming back to Chepstow where Turner painted it at the age of 19.

“It will become the jewel of Monmouthshire’s collection of paintings and drawings inspired by the Wye Valley.

“I hope today’s young artists will see it and be inspired.

“We had thought purchase of a significant artwork like this was out of reach, until generous funders stepped in to save the painting for the nation and for Monmouthshire.”

Funding for the purchase came from Arts Council England, the V&A Purchase Grant Fund and National Lottery support, Museums Association Beecroft Bequest and The Usk Valley Trust.