The Office of Public Sector Information (OPSI) has grown out of Her Majesty's Stationery Office (HMSO). It is central to national information policy, setting standards, delivering access and encouraging re-use of public sector information. OPSI provides online access to UK legislation; licenses the re-use of Crown copyright material; manages the Information Fair Trader Scheme; maintains the government Information Asset Register; and offers advice and guidance on official publishing and Crown copyright. HMSO continues to exist and fulfil its core activities including responsibility for the publication of legislation and the management of Crown copyright operating from within OPSI. The legislation link provides access to UK Acts, UK Statutory Instruments, Acts of the Northern Ireland Assembly, Northern Ireland Statutory Rules, Acts of the Scottish Parliament, Scottish Statutory Instruments and Statutory Instruments made by the National assembly of Wales.

Legislation.gov.uk brings together the legislative content currently held on the OPSI website and revised legislation from the Statute Law Database (L136001) to provide a single legislation service that replaces the OPSI and Statute Law Database services from 2010.