A fourth UK Research Councils has issued a self-archiving mandate for all the research papers it funds. The Natural Environment Research Council (NERC) will require from 1 October 2006 that copies of peer-reviewed papers resulting from new funded awards be deposited at the earliest opportunity in an e-prints repository. NERC will establish an institutional repository for the work of its staff members and this repository will be available for authors whose institutions do not have their own repository. Now half of the UK Research Councils have strong self-archiving mandates in place.