Many automatic fire detection systems are extended by means of automatic "999" diallers. These normally pass a recorded message via a manned GPO telephone exchange to a fire brigade control room. Since information was not readily available on the number of such installations existing in the United Kingdom, a sample of twenty six fire brigades was approached by telephone and asked how many they were aware of in their areas. Although most expressed some reservations on the completeness of their knowledge nearly all were able to supply approximate figures. From these, some idea of the National total can be derived.