Question to the Foreign, Commonwealth & Development Office:

To ask the Secretary of State for Foreign and Commonwealth Affairs, whether he has commissioned research to determine what the UK's obligations in international law are in the event of economic or environmental damage being caused to other countries by radioactive fallout or blast arising from a British nuclear weapon being (a) accidentally detonated or (b) deliberately targeted and the effects spread to a third or more of the country.

This question was answered on 18th December 2014
We have not commissioned any research. The issues are long-standing, and the Government has not seen the need to commission fresh research.