Britannica is still the most the popular educational encyclopaedia, and Wikipedia grew online only to move now onto CD.

In a mission to make knowledge available to everyone, the Wikipedia discs will be sold at approximately £7 and contain 2000 articles, out of the 1.7 million.

The Wikipedia Version 0.5 CD collection includes topics such as geography, arts, literature, science and history. The articles were selected by software that rated their quality and importance to the Wikipedia community.

Wikipedia has come under attack for the way anyone can update the information, with articles being incorrect or ambushed by attacks.

"We wanted to cover the major topics, while also including a selection of articles considered to be the very best of Wikipedia", said Professor Walker, of the State University of New York, Potsdam.