The nine British and Irish species of Enicospilus are revised, mapped and an identification key provided. One species, Enicospilus myricae sp. nov., is described as new; Enicospilus merdarius (Gravenhorst, 1829) is a senior synonym of E. tournieri (Vollenhoven, 1879) syn. nov.; the only available name for E. merdarius auctt. is Enicospilus adustus (Haller, 1885) stat. rev., and a neotype is designated for Ophion adustus Haller, 1885. Enicospilus cerebrator Aubert, 1969 and E. repentinus (Holmgren, 1860) are newly recorded from Britain. Some host data are available for eight of the nine species.