Heh! AS IF Iran didn't have far more pressing matters much closer to home to deal with than the completely lunatic notion that they would lob a nuke at the British Isles! It would be a useless and suicidal thing to do, and it would achieve absolutely nothing that Iran could possibly wish to achieve at this point in their history...

Iran is the one who needs a deterrent. They have the Sixth Fleet off their shores, and occupying American and British forces based right across their borders with Iraq and Afghanistan. I have seldom seen anyone who needed an effective deterrent more than Iran does right now.