The secret recipe for Lea & Perrins’ Worcestershire sauce was found in a skip 20 years ago, it has emerged.

The discovery was made by the manufacturer’s former accountant, Brian Keogh, who died three years ago. It had been kept by his daughter among other documents he had collected over the years and will be put on display at the Worcester City Museum.

“We’re still protecting the secret of the recipe,” Keogh’s daughter, Bonnie Clifford, told the Daily Express. “It’s interesting to see how the recipe has developed over the years but it hasn’t changed that much,”

The museum is analysing the handwriting to check the recipe is authentic. Lea & Perrins first commercialised the sauce in 1837 but never revealed how it was made.