A valuable secret has been hiding beneath the floorboards of a sporting goods store in the UK since World War II. As the BBC reports, about £30,000 in roughly 80-year-old British bank notes was unearthed by a renovation project at the Cotswold Outdoor store in Brighton. Adjusting for inflation, their value would be equal to roughly $2.5 million today.

Owner Russ Davis came across the hidden treasure while tearing out decades-worth of carpet and tiles beneath the property. What he initially assumed was a block of wood turned out to be a wad of cash caked in dirt. Each bundle held about £1000 worth of £1 and £5 notes, with about 30 bundles in total.

The bills are badly damaged, but one surviving design element holds an important clue to their history. Each note is printed in blue, the color of the emergency wartime currency first issued by the Bank of England in 1940.

At the time the money was buried, the property was home to the famous British furrier and couturier Bradley Gowns. Prime Minister Winston Churchill and his wife, Lady Clementine Churchill, were reportedly regular customers.

The reason the fortune was stowed beneath the building in the first place remains a mystery. Davis imagines that it might have come from a bank robbery, while Howard Bradley, heir to the Bradley Gowns family business, suspects it might have been stashed there as a getaway fund in anticipation of a Nazi invasion, as he told the New York Post.

The hoard will remain in the possession of the Sussex police as more details on the story emerge.

[h/t BBC]