The legal framework for the regulation of medical research on human beings has not been set out in legislation. As a result, many developments have taken place through the publication of official circulars and guidance. For example, the current framework for the functions and operation of Research Ethics Committees is described in the Department of Health document Governance Arrangements for NHS Research Ethics Committees (July 2001). This document replaces the Department of Health circular HSG(91)5 which required District Health Authorities to set up local Research Ethics Committees (LRECs) in 1991, and circular HSG(97)23 which dealt with the establishment of Multi-centre Research Ethics Committees (MRECs) in 1997. (These documents apply to England and Wales, but there are equivalent documents for Scotland.) These official publications do not have the same legal force as legislation. Therefore, Research Ethics Committees do not have the legal status of a statutory body, with clearly defined legal powers and duties. Thus, any authority that an Ethics Committee wields is informal and extralegal. Such authority should not, however, be underestimated. Within the National Health Service, the Governance Arrangements for NHS Research Ethics Committees places a clear responsibility upon Health Authorities to set up, support and monitor NHS Local Research Ethics Committees, and the Department of Health's document, The Research Governance Framework for Health and Social Care (2001), states: ‘The Department of Health requires that all research involving patients, service users, care professionals or volunteers, or their organs, tissue or data, is reviewed independently to ensure it meets ethical standards.’