Leading article: Disarmament through diplomacy

The disagreement appears to stem from different interpretations of the Paris agreement. The Iranian government claims that the EU promised to present a package of incentives for it to scale down its nuclear ambitions by today at the latest - and that since no package has been forthcoming it will restart the reactors. But France, Germany and Britain - which represent the EU - argue there was no rigid deadline and warn that if Iran proceeds with its programme, it is itself in breach of the agreement.

Iran could be just trying to speed up the delivery of the incentives package; several measures would be a great help to it economically, such as lifting the block on its membership of the World Trade Organisation.

But the greater danger is that Tehran has decided to step up its nuclear programme solely on national security grounds - that it is now determined to develop its own nuclear weapon. That could rapidly turn this diplomatic spat into a full-blown crisis. The new Iranian President is due to take office this week. Mahmoud Ahmadinejad made it clear during June's election campaign that he would fight for Iran's right to enrich uranium. The worry among diplomats will be that yesterday's announcement is the first sign of a new, harder line regarding nuclear weapons.

The task of the international community is to convince Iran that its interests are not served by becoming a nuclear power. Yet so much that the West is doing undermines that objective. By labelling Iran a member of an international "axis of evil", US President George Bush stoked the fires of insecurity. Iran must also look to the near collapse of the 1968 Nuclear Non-Proliferation Treaty and wonder exactly why it should refrain from following the nuclear route? It will not have escaped Tehran's notice that the big powers have made virtually no efforts to diminish their own nuclear stockpiles in recent years.

Diplomacy remains the only sensible approach to dealing with Iran and its nuclear programme. But those seeking to persuade it to abandon the bomb are opening themselves up to the charge of narrow self-interest and hypocrisy.