Leading article: A policy of calm remains the best course with Iran

It would be naïve to believe that Iran won't now use the British seamen taken from their yacht after straying into Iranian waters for political purposes. It would be equally unwise to treat the incident as a major confrontation in which Britain must demand of Iran immediate release or face the consequences. For what are those consequences?

From Tehran's point of view, the country already faces a hostile West determined to isolate it and bludgeon it into compliance with their demands on its nuclear ambitions. Further confontration with the West carries with it no additional risks and could even benefit the besieged administration at home by staging a public tweaking of the tail of the British lion, as it did with the UK Marines seized two and a half years ago.

That is the difficulty of dealing with Iran today. On the one hand the West wants its co-operation on a whole range of problems in the region. On the other hand the international community is also driven by a profound distrust of the country's motives and a fear of its behaviour. Iran, for its part, has meanwhile developed a deep distrust (born of some experience it should be said) of western intentions towards it and its regime. Push it too hard and Iran reacts by doing the opposite of that demanded, isolate it and Iran just battens down the hatches and withdraws into itself.

The situation has been made infinitely more delicate, and less predictable, by the disputed re-election of President Ahmadinejad last summer and the consequent brutal and gradually intensifying clamp-down on his opponents. In dealing with Tehran today it is now extremely difficult to know how far you are being sucked into an internal battle for power and just who you are, or should be, talking with.

Tehran's announcement last week that it would be building 10 new uranium enrichment plants, for example, could represent a sudden lurch to confrontation led by the nationalist and anti-western forces within the government or equally could be a negotiating ploy aimed to counter western threats of sanctions. Or then again it might be a piece of theatre orchestrated largely for domestic consumption. Those who have always doubted Iran's good faith and believe it intent on developing nuclear weapons regard the statement as proof of its untrustworthiness and call for a ratcheting up of sanctions and threats of military attack. Those who see it more as part of a pattern of threat and counter-threat started by Washington, put it down to Iran's reaction to recent resolutions against it by the IAEA and western calls for more sanctions.

Under pressure domestically, not least from the deteriorating economic situation, President Ahmadinejad and the supreme ruler, Ayatollah Khamenei, have seen in outside pressure a useful means of wrapping their own fragile position in a stiff flag of patriotic resistance to foreign threats and a reason to clamp down on the opposition at home.

Issuing demands at this point, whether over the sailors or the nuclear issue, can only be counter-productive. The truth is that we don't really know what Tehran is up to. What we can say is that Iran, so far, remains a member of the Nuclear Non-proliferation Treaty and has pledged itself to act according to the law in the case of these sailors. So long as that is true, we are best keeping calm and giving it the benefit of the doubt. It is a proud and important country and should be treated as such. Empty threats will only serve the purposes of the more oppressive elements in the regime.