IT will store seven million books and documents, has cost £26 million to build and uses robotic cranes to retrieve items from the shelves.

Welcome to the new extension to the British Library at Boston Spa – the most advanced library storage facility in the world.

The huge building, opened yesterday by Regions Minister Rosie Winterton, will store 262 kilometres worth of items in a temperature and humidity controlled environment to aid their preservation.

The air has low oxygen levels, similar to that found 3,000 metres up a mountain, to prevent fire breaking out.

Items will be stored in 140,000 bar-coded containers, which can be retrieved automatically by seven robotic cranes which sweep up and down the storage void.

Two lorryloads of books and documents, including patent specifications, are being taken to Boston Spa each day as the British Library vacates a range of buildings in London, but not its St Pancras headquarters. A spokesman said the extension would help safeguard the jobs of 900 employees at Boston Spa, of whom 200 to 300 live in York. He said planners at Leeds City Council would later this month consider a separate £33 million scheme for another building to store the national newspaper collection, which would hold every single copy ever published of papers such as The Press and its predecessor the Yorkshire Evening Press.