The national recording scheme for Hoverflies (Diptera, Syrphidae) in Great Britain, affiliated to the Biological Records Centre. A good point of contact is the British Hoverflies Facebook page. The Scheme publishes a Newsletter twice a year. These are delivered with the Bulletin of the Dipterists Forum and are available from their website.
This website is designed to make summaries of the data, such as species distribution maps and phenology plots, available. Use the taxonomic tree to the left to locate the species you are interested in. "Coverage" shows the extent of information that has been received. "Gallery" shows all the pictures of hoverflies available.
Information about when the summary data presented on this site was last updated is here.