The 2010 Charting Progress 2 assessment (UKMMAS 2010) subdivided UK waters into eight regions to assess how human use and other pressures were affecting the productivity of UK seas. Regional boundaries were developed in 2009, adapting 'regional seas' previously identified on the basis of physical and biological biogeography by the Review of Marine Nature Conservation (RMNC) 2004. The CP2 'Reporting Regions' have subsequently informed a variety of MPA designation, marine assessment and reporting purposes and continue to be used, for example in the selection of Highly Protected Marine Areas, indicators for the ecological status of the water environment, and the aggregation of marine biotope sensitivity information.
JNCC updated the CP2 Reporting Regions dataset in 2025, making improvements to the outer maritime boundaries of CP2 regions to align with the UK Exclusive Economic Zone (EEZ) and UK Continental Shelf (UKCS) limits (across UK) and Isle of Man Territorial Sea limit.
Note that the use of the CP2 Reporting Regions (or other biogeographic regions and assessment units) by JNCC, the SNCBs and other ALBs will vary by purpose. Variations of the CP2 Reporting Regions may be used for assessment purposes.
Data notes and limitations:
• open data coastline datasets used in the 2022 update were of medium spatial resolution, lacking detail in some areas (e.g. sea lochs and islets in the Hebrides, Orkneys and Shetland, pladdies in Strangford Loch and islets around Northern Ireland).
• part of the Scottish Continental Shelf (region 7) boundary was originally drawn to align with the UK Territorial Waters limit around Orkney and Fair Isle. This section of boundary has not been updated and therefore remains consistent with the biogeographic boundary created in 2009.
• in the absence of formally agreed maritime limits, linework from the original 2009 CP2 Reporting Regions data set has been retained to represent the boundary between the Northern Ireland Inshore Region and Republic of Ireland inshore waters.