A woman appearing on the BBC’s Antiques Roadshow earlier this year was shocked to learn that her dad’s old watch, which he bought for just £20 ($25) dollars in the early 1970s, is a rare collectible item that could be worth as much as £10,000 ($12,500).

On a sunny day at Powis Castle in Wales, the woman showed the timepiece to antiques specialist Richard Price, who remarked on its impressive size and weight. He explained that it was originally made to be worn by a pilot, in this case a member of the German Air Force, or Luftwaffe, during World War II.

To match the large clock face, it would have had a “a massive leather strap that went around a big, heavy flying jacket,” said Price. It was also designed to be readable in the dark.

“Like all wartime watches with luminous paint, this is painted with the radioactive material radium,” Price warned. “If you are going to take it apart, then please seek specialist advice.”

Timepieces like this one were produced in factories, and Price pulled off the watch’s reverse to reveal its whirring cogs and a manufacturing mark referring to A. Lange & Söhne in Glashütte, Germany, a town that is considered the birthplace of the German watchmaking industry. “When the Russians were coming in to Berlin to take the city in May 1945, they bombed this place to annihilation,” Price said. “The Lange factory was destroyed.”

“It is the rarest of all the manufacturers and the one that collectors all want,” he added. To the woman’s amazement, he revealed that the watch is worth between £8,000 ($10,000) and £10,000 ($12,500).

“Lucky my dad!” the woman exclaimed, adding jokingly: “I might not take it home to him!”

She revealed that her father had chanced upon the wristwatch in the early 1970s in the seaside town of Weymouth in the west of England. “He was always poking around old antique shops and government surplus places,” she said.

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