James Forsyth has this prescient little piece on Iran's nuclear ambition. I remember when James and I were contemporaries at Cambridge; this was simply not on the mainstream radar, but the signs were there for anyone to read.
The simple truth is that the Nuclear Non-Proliferation Treaty (NPT) regime has never been an effective mechanism for preventing state-based proliferation of nuclear weapons. To the best of my knowlege, neither we, nor any of the P5, have ever taken seriously our Article VI commitment to nuclear disarmament.
British and American attitudes to nuclear proliferation are shaped from within our respective national contexts of being nuclear powers. If we lacked nuclear weapons but Iran had them, we would be doing our level best to acquire them as fast as possible. Mutatis mutandis, Iran's position is intelligible.
We lack credible policy levers to prevent Iranian nuclear armament. We should, therefore, cut our losses, accept that we live in an age of state-based nuclear proliferation, and focus our policy on convincing Pakistan and Iran that their selfish national interests are aligned with our commitment to ensure that non-state terrorists do not acquire nuclear material.
The world can, and probably must, live with a nuclear Iran. In contrast, I don't think the world is well served by the self-serving but ineffective NPT status quo ante.