Concern for the protection of the environment and conservation of its natural resources was given an official expresssion in the 1972 Stockholm Conference on the Human Environment. Subsequently environmental law (including international environmental law) will be considered as one component of environmental protection techniques and UNEP proposed, as a 'catalytic' body, to use, among other things, environmental law activities where environmental law is found defective, insufficient or completely non-existent. This thesis examines the role and achievements which UNEP has made in the development of international environmental law, whether substantive law, procedural law or institutional law and looks at whether UNEP's activities and achievements in this field have yielded a model which has been, or could usefully be, applied by States when concluding agreemlents among or between themselves.