In 1991 the British Academy - Royal Historical Society Joint Committee on Anglo-Saxon Charters resolved to produce a revised, updated and expanded edition of Sawyer's catalogue. The first stage in this process, undertaken by Dr Susan Kelly, commenced in 1994. Attention was focussed on the 'main' sequence of entries (S1-1602), leaving the 'Lost and incomplete texts' (S 1603-1875) to one side. The separate entries were revised systematically: summaries were checked (and further information added); bibliographical data was reorganised; and references were collected from books and articles published between 1968 and 1998. New entries for charters which had come to light since 1968 were created, and inserted at appropriate places in the main sequence. Corrections and additions were incorporated from annotated copies of 'Sawyer' provided by Professor Simon Keynes and others.
Dr Kelly completed her task in December 1998, and in January 1999 the 'Revised Sawyer' (S 1-1602) was made available on the committee's website. At the same time, provisional texts of many of the charters were made available on the website as 'Regesta Regum Anglorum', developed by Dr Sean Miller. In 2001 the 'Revised Sawyer' and the 'Regesta Regum Anglorum' were amalgamated by Dr Miller in a database, and made available on his 'anglosaxons.net' website.
A new research project, to complete work on the 'Revised Sawyer' (for publication in book form), was set up in 2003. The project, based in the Department of Anglo-Saxon, Norse, and Celtic, University of Cambridge, was funded by the AHRC. Dr Rebecca Rushforth converted the ‘Revised Sawyer’ into an electronic database, with a view to its publication online, in a fully searchable and updatable form, to be complemented in due course by publication of a new and fully revised edition of the book. Dr Rushforth also checked publications back to 1971, and collected additional references, especially for the period from 1998 onwards. In 2006, with funding from the AHRC, David Pelteret prepared electronic texts of all those charters which had by then been published in the new edition, extended by provision of texts for Christ Church, Canterbury (ed. Brooks and Kelly); he also made some fresh translations of charters in certain archives. These texts and translations were duly incorporated into the Revised Sawyer database. In 2008, further citations of charters from recent publications were collected by Rory Naismith, Levi Roach, and David Woodman (then graduate students in the Department of Anglo-Saxon, Norse, and Celtic, University of Cambridge); this data has not yet been uploaded to the Revised Sawyer database, and thus does not appear in the Electronic Sawyer (2010).