A Foreign, Commonwealth & Development Office spokesperson said:
The UK welcomes the decision to extend New START. We have long supported such an extension: we value New START for its contribution to strategic stability, transparency and building trust. We are glad to see the Treaty, and its robust verification mechanism, continue.
Building on the spirit of cooperation fostered by the extension of New START, we also support wider US efforts to engage on new arms control challenges. Since New START was agreed, the global context has changed significantly, with the development of new strategic and other weapons systems not covered by any arms control agreement. We will continue to work with the US and our other Allies to address this issue.