A vast collection of hitherto unseen historical documents stored at the World War II code-breaking centre at Bletchley Park, Buckinghamshire, is to be digitised and made available to the public online.

Expected to take between three and five years, the collaboration between electronics company Hewlett-Packard (HP) and the Bletchley Park Trust will help to commit more than one million of the site's historic documents to digital format. The documents include communication transcripts, communiqués, memoranda, photographs and other material tracing and referencing some of the most significant events of the Second World War.

HP has donated a range of Scanjet scanners and a ProLiant ML330 server to Bletchley Park, enabling the site to scan and store the data. HP will also be providing document management software to handle its cataloguing and virtual management.

The high-level intelligence produced at Bletchley Park - codenamed Ultra - during the war provided crucial assistance to the Allied war effort, including the decryption of many of Germany's military communications generated by the Enigma (thought to be unbreakable) and Lorenz coding machines. The success of the top secret facility is estimated to have reduced the length of the war by two years.

The project will need to take into account not only the sheer volume of paper-based materials involved, but also the dozens of different formats presented by the documents, including multiple page types, sizes, qualities and material compositions.

Following an initial digitisation phase lasting a year or more, Bletchley Park will make the content available for access using a combination of paid-for and free content.

The Bletchley Park site is home to, among others, the story of Alan Turing, father of the modern computer; the achievements of numerous spies and spymasters such as Zigzag, Garbo and James Bond author Ian Fleming; and some of the technology - represented by the Enigma, Bombe rebuild, and Colossus machines - which heralded the development of the modern computer and the start of the information age.