This article is aimed at those professional scientists and engineers who believe that issues of international peace and security are too important to be left to the politicians. Nuclear Terrorism is a hostile act (or a threat of such an act) involving nuclear materials (fissile or radioactive) performed by a terrorist, a term which covers a wide range of individuals. What they all have in common is that, for some reason they have become motivated to hurt or destroy sections of society which they have come to regard as the enemy; their motivation varies enormously. They also vary enormously in the extent and nature of their technical/scientific education.

There are 'PhD terrorists' and 'Peasant terrorists', and they differ greatly in the threat that they represent, and the steps which can appropriately be taken to counter it. The most serious threat comes from the potential ability of terrorists to steal or manufacture nuclear weapons of mass destruction (e.g. capable of causing thousands of deaths). Unless the underlying causes of terrorism can be quickly removed, we have a duty to mankind to make terrorist access to such weapons, and to the nuclear materials which are their essential ingredients, as difficult as possible.

Improvements in the arrangements for denying unauthorised access to radioactive material should be made such that the protective measures made are proportionate to the number of Curies at risk and the likelihood of a terrorist initiative. The preventative measures, sadly, need to take account of the possibility that the terrorist will use lethal force to access the material.