The Biological Records Centre (or BRC) is the group responsible for recording and keeping records on fresh water and terrestrial species in the UK.
In addition to the national organisation with this name, there are also local biological records centres ("local records centres") within the UK. These have a complementary role as systems "for collating biological data from a wide range of sources (including organisations and individuals), for ensuring that data are properly validated and catalogued, and for providing access to them, thereby acting as a focus for biological information."
More information on this dataset can be found in the Freshwater Metadatabase - BFE_67 (http://www.freshwatermetadata.eu/metadb/bf_mdb_view.php?entryID=BFE_67).