The coral forms large bushy colonies which can be fixed to the substratum or free. The polyps are translucent and have up to 50 tentacles with obsolete terminal knobs. The colour is white, pink or yellowish. In British and Irish waters, Lophelia pertusa colonies occur in groups which are no more than 5-10 m in diameter and often smaller. Individual polyps are connected by their external calcareous skeletons. The skeletons of individual polyps are up to 12 mm in diameter.Lophelia pertusa reefs provide a habitat for a variety of species and the living and dead coral skeletons provide a biodiversity 'hot spot' on the edge of the continental shelf (Jensen & Frederiksen, 1992; Mortensen, 2001). The deep waters where Lophelia pertusa reefs occur were undisturbed by human activity until recently. Fishing trawlers are now operating in the deeper water where Lophelia pertusa occurs and causing damage to the reefs (e.g., Hall-Spencer et al., 2002). Oil extraction from deeper waters may possibly cause damage to the reefs (see e.g., Roberts, 1997; Rogers, 1997, 1999). The implementation of the Habitats Directive to the limits of the EEZ and the adoption in 1998 of a new Annex to the OSPAR Convention (1992 Convention for the Protection of the Marine Environment of the North East Atlantic) may offer an opportunity to protect important deeper water or offshore habitats and species, such as Lophelia pertusa. For further information see COR.Lop.