The Complete Diptera of Lancashire and Cheshire by Phil Brighton is now available online via the Lancashire and Cheshire Fauna Society and North West Invertebrates. Updated to the end of 2025, this landmark work provides the first fully comprehensive account of the flies (Diptera) of the region, covering vice-counties 58, 59 and 60, and bringing together more than a century of recording effort.

The publication collates 142,827 occurrence records for 3,633 species, representing just under half of the entire British Diptera fauna. Data have been drawn from the NBN Atlas, iRecord, Manchester Museum card indices, World Museum Liverpool surveys and the author’s own records, and standardised to a consistent 1 km / yearly resolution.

Alongside a full species checklist, the report includes summary tables, long-term trends in recording from 1900 to 2025, and a set of maps showing changes in recorded species richness across the region. Notable findings include the importance of the Delamere Forest area, identified as the region’s most species-rich hectad for larger flies (but not accounting for recorder bias). Appendices provide excluded species and frequency data for all recorded species.

The report can be navigated via PDF bookmarks and is intended as a key reference for entomologists, conservationists and recorders. Despite the long history of Diptera recording in the region,  there are still big gaps in taxonomic and geographic coverage.

The author hopes it will encourage and guide future recording, analysis and conservation of one of Britain’s most diverse insect orders.