You can identify an earthworm by looking at a number of external features, such as the head, male pour and clitellum. Because earthworms are small you need a microscope and an identification guide. If you are looking a British there is a key to the 31 different species of earthworms.
To buy the UK and Ireland Earthworm Identification Guide please visit the Field Studies Council Publications page.
If you are interested in identifying and recording earthworms please visit our Earthworm Recording Scheme pages.