A rare British military wristwatch which was issued during the Second World War has sold for almost £20,000 at auction - nearly double than experts expected.

The watch has a stainless steel case with manual wind movement and is one of the famous 'Dirty Dozen' watches.

It was discovered during a house clearance in Swansea and then taken to Rogers Jones and Co Auctioneers and Valuers at their office in Carmarthen.

The watch went under the hammer at auction in Cardiff

uctioneer Charles Hampshire said: "The 'Dirty Dozen' consisted of 12 military issue wristwatches produced in the mid 1940s and designed to be rugged, accurate and reliable.

"This is an extremely rare watch and likely a once in a career find if you are lucky.

"They are only a handful of full collections consisting of all 12 examples and many people struggle to source the Grana due to the very small production numbers."

The watch was expected to fetch around £10,000 but such was the level of interest that ultimately it sold for £18,000.

Charles said following the sale: "It made a joint auction record of £18,000 hammer price.

"It was the most viewed and enquired lot in the lead up to the sale with global interest on the day including bidding from the Netherlands.

"It really is an extremely rare and important military watch which I have been privileged to handle for a short period of time.

"These rare timepieces are out there often languishing in a drawer and we would be delighted to assist in offering them to a global market in one of our specialist auctions held in Cardiff."

The 'W W W' engraved on the rear of the watch simply stands for 'Watch, Wrist, Waterproof' with approximately 1,000 to 1,500 examples of the Grana edition produced resulting in it being the rarest and often the most coveted of the watches.