In Britain the concept of legal deposit, whereby a publisher established their ownership of a text by depositing copies in named libraries, was first defined by the Licensing Acts of 1662 and confirmed by the Copyright Act of 1709 and its subsequent revisions. Cambridge University Library has always been one of the named legal deposit libraries. Currently there are six. A publisher must give a copy of each publication to the British Library in London. Five other libraries are entitled to claim a copy free of charge within one year of publication: the Bodleian Library in Oxford, Cambridge University Library, the National Library of Scotland in Edinburgh, the National Library of Wales in Aberystwyth and Trinity College Library in Dublin. In practice the Copyright Agency in Edinburgh claims five copies of each publication and distributes them to the libraries.

Originally legal deposit covered only printed material, including books, journals, newspapers, maps and sheet music. Other media, such as LPs, cassette tapes, CDs, DVDs and CD-ROMs, were excluded. However, under the terms of the Legal Deposit Libraries Act 2003, which came into force with the passing by Parliament of the Legal Deposit (Non-Print Works) Regulations in April 2013, legal deposit was extended to electronic publications.

Deposited electronic texts are processed by the British Library and stored (e.g. journal articles as PDFs, ebooks in epub format) on British Library servers in London and Boston Spa, West Yorkshire and on others in the National Libraries of Scotland and Wales. Access from designated PCs in Cambridge libraries is via a secure link to one of these servers. Records are also supplied by the British Library to the other legal deposit libraries for inclusion in their catalogues.

When deposited, electronic publications and websites are not accessible for at least seven days.