Nuclear weapons may be filthy, but they are a comparatively clean way of deterring people from using biological and chemical weapons which are worse.

Countering the spread of WMD is one of the most important challenges we face in building a peaceful and secure 21st century. Whilst public attention is always focussed on nuclear issues, that doesn't just mean countering those illegal weapons programmes.

It is abundantly clear to all, including the Iranian regime, that the West has intent to cause regime change in Iran. The new sanctions announced this week are a clear step towards that goal. It is the beginning of moves that the Iranian freedom movements have been asking the West for for some years.