In October 1971, the Council of the European Community ratified a directive on units and measurements (EEC, 1971) which provides for the exclusive use by January 1, 1978 of a prescribed system of metric units. This system is firmly based on the International System (SI) as agreed by the General Conference of Weights and Measures, and its strict application could result in the eventual abandonment of the “special” radiological units, the roentgen, the rad and the curie. Indeed steps in this direction have already been taken in two European countries. In a recent Government White Paper (Metrication, Cmnd 4880, 1972), it is clear that the EEC directive would apply to the United Kingdom as a member, though special arrangements have been negotiated to retain certain imperial units until December 31, 1979, or longer in some cases. The British Committee on Radiation Units and Measurements (BCRU) has already discussed this matter and is concerned that wider consideration should now be given to the concepts involv...