A bone scanner cracks the code of a 400-year-old Welsh shipwreck padlock after the detectorist who found it spent 20 years failing

The brass padlock from the Ann Francis — an Elizabethan merchant vessel wrecked off Margam Beach, Port Talbot, in December 1583 — had defeated every attempt to open it for over four centuries. Cardiff University's Dr David Williams used micro-computed tomography, a scanning technique normally reserved for examining bones, to build a 3D image of the internal mechanism and identify the combination. Metal detectorist Peter Hughes, who recovered the lock and a hoard of gold and silver coins from the wreck between 1996 and 2017, had spent two decades manually trying every combination before giving up.

Hughes compared his fruitless 20-year attempt to cracking the 'Da Vinci Code'; Williams said receiving confirmation they had succeeded was 'incredibly satisfying'.

Researchers believe the lock once secured a captain's chest holding Spanish silver, high-value textiles, or sensitive maritime correspondence.