At a time when the subject of arms embargoes and arms export control is arousing considerable interest both at home and abroad, it is not untimely to examine the system of control which has developed in one of the chief arms producing and exporting countries of the world—Great Britain. Much attention has been devoted to the alleged evils of the international traffic in arms, and to the desirability of an effective government control over all armaments exports. Little consideration, on the other hand, has been given by writers to the question of how such control should be administered by a government, and what measures are actually involved. Taking the experience of Great Britain as a case study, the writer proposes in the following pages to trace the development of arms export control in that country, to examine the ways in which it has been administered, and to point out some of the difficulties which have been encountered. The present article may be looked upon, therefore, as a case study in the broader subject of national controls over the export of war materials.