David Moss, from Cheshire, found up to 15,000 coins contained within two clay pots at a “virtually untouched” location in north Wales this August. The 36-year-old, who has been detecting for nearly a decade, said he had “goosebumps” after making the discovery with his friend, Ian Nicholson.

Fearing the significant find could be stolen, Mr Moss slept in his car for three nights to guard the hoard before he could deliver it to experts. “I just didn’t want to leave it out of my sight,” he explained.

The coins are now being assessed at the National Museum Cardiff. Experts believe the discovery could surpass the previous largest hoard found in Wales, which consisted of around 10,000 coins unearthed near Chepstow in the 1990s, BBC reports.

Anthony Halse, chairman of the South Wales and Monmouthshire Numismatic Society, suggested the hoard might represent the savings of one or more Roman soldiers, buried for safekeeping. Such hoards were often buried during periods of turmoil or as religious offerings.

Once museum experts have cleaned and dated the coins, a valuation will take place. Under the Treasure Act, any reward is typically split between the finder and the landowner. The museum’s full assessment is expected to be completed next year.