Grasmere Gingerbread is made using a 150-year-old secret recipe so secret, that it is locked away in the National Westminster Bank in nearby Ambleside. "My husband and father know it and that’s it. I don’t even know it," says Joanne Wilson of Sarah Nelson’s Grasmere Gingerbread. "My son who is four said, ’Don’t tell me the recipe, daddy, otherwise someone will kidnap me.’

"All our members of staff have signed secrecy and confidentiality agreements, although it is only my husband that mixes the ingredients and, therefore, the recipe is kept a secret," adds Wilson.

The shop has some famous fans, including Tom Cruise, Nicole Kidman and Renée Zellweger who was recently filming in the Lake District for the film Miss Potter. "Renée was quoted in the regional newspapers and on an American chat show, saying that it was the best gingerbread she has ever tasted," says Wilson.

The gingerbread shop is located in Grasmere - a well-known tourist attraction, as it is home to William Wordsworth’s grave and cottage. In fact, the bakery building, built in 1630, was originally the village school where Wordsworth once taught. Measuring just 6ft by 6ft in the shop, with the two bakery rooms at 9ft by 9ft each, the set up is tiny.

Over the years, little has changed. The school coat pegs are still in place and so is the cupboard used to house the school slates. In 1850, a poverty-stricken woman named Sarah Nelson rented the property. She started to make the gingerbread for Victorian tourists and it is her recipe that is still used. Apart from gingerbread, it also makes rum butter, homemade fudges and jams.

The shop has been in the Wilson family for over 70 years. Third-generation Joanne Wilson is in charge of sales, marketing and PR, and her husband Andrew Hunter bakes. The shop and bakery have eight members of staff, two of which have been with the company for over 18 years.

The bulk of its customers are tourists visiting the Lakes. "Ginger acts as an aphrodisiac, so our shop is wonderful for couples escaping to the Lake District National Park for romantic weekends," says Wilson. It also mails out the gingerbread to people as far afield as the USA, China and Japan. "There’s a lot we want to do with the business," says Wilson. "But if we mass-produced the gingerbread, it would kill what we are about. Money is not our primary concern. We have been approached by several retailers and wholesalers. But this would take away the integrity and uniqueness of the product."