An exceptionally rare Rolex watch bought for just £69 in Doncaster in 1966 could fetch as much as £120,000 when it goes under the hammer.
The Rolex Submariner 5513, bought from a jewellery shop in Doncaster, is one of only a small number manufactured in the early 1960s with an Explorer 3-6-9 dial - a dial showing the numbers three, six and nine.
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The vast majority of Rolex Submariners have no numbers on their dials.
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Still in its original condition, the watch comes complete with its receipt, guarantee booklet and a 1965 Rolex sales catalogue, having been owned by the same person since purchase.
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Auctioneer David Hare, from Gardiner Houlgate auctioneers in Wiltshire, said: "This is a very rare and desirable watch that's going to attract interest from private collectors and dealers all over the world.
"What makes this watch particularly desirable is its condition and the fact it has excellent provenance.
"Because of their value, counterfeiters do attempt to fake these watches.
"It's a stroke of luck that the owner of this watch never had it serviced. If he had, Rolex may have replaced the 3-6-9 dial and the value of his watch would have dropped from over £100,000 to around £5,000.
"This is the eighth Submariner with an Explorer 3-6-9 dial we've sold in recent years - that's more than any other auction house in the UK.
"We've developed quite a reputation for handling these and we're keen to hear from anyone who has one.
"It's very unclear how many still exist. I suspect there are owners out there who don't realise the significance of the Explorer 3-6-9 dial.
"If you have a Rolex Submariner from this period, which wasn't hugely expensive to buy at the time, check the dial."
Rolex designed its Submariner watch for use by recreational and professional divers.
The watch will be sold on May 23 along with more than 500 other lots.