THE UK’s largest underground storage company, based down Winsford Salt Mine, is celebrating a milestone – it has increased the number of boxes it manages by 30 per cent in the past five years to 2.5 million.

To accommodate the growth, DeepStore is expanding by an extra 32,549 square metres of space within Britain’s largest salt mine – in an area called Bostock 2, which is equivalent to eight times the size of the Wembley football pitch.

The mine is owned and managed by DeepStore’s parent company, Compass Minerals, which has the capacity to mine 1.5 million tons of rock salt annually, 150 metres below the surface.

Craig Trimby, DeepStore’s head of sales, said: “Achieving 2.5 million boxes and expanding into this new area is a major milestone for DeepStore. The new space enables the future growth of the business and, with the continuous rock salt mining activity, we have the capacity for future expansion into an area of more than 500 million cubic feet so we will never be short of space.”

The mine provides the ideal environment for storing documents as it has consistent temperature and humidity levels that meet the highest specification requirements for the storage of archival material. Its storage areas also are naturally free from ultraviolet light, vermin and flooding.

The area under DeepStore’s control continues to grow as salt is mined every year.

DeepStore has a vault space of more than 700 football pitches and more than 1,000 public and private sector clients and stores.

It is associated with a number of records management professional bodies, including the Information and Records Management Society and the Business Archive Council.