Leading article: The pitfalls of nuclear diplomacy

If you wanted to encourage Iran to pursue negotiations on the nuclear issue, the last thing you would do is to reveal publicly that they had talked face to face with the Israelis on the question. The Iranians deny it, of course, and the Israelis, while accepting it did happen, have been keen to play down its significance. Such meetings have happened before without fuss, they say.

True. But the occasion, at a session of the International Commission on Nuclear Non-Proliferation and Disarmament conference in Cairo last month, was certainly relevant. The fact that Iran was prepared to sit at the same table as its avowed enemy could bode well for the current talks between the International Atomic Energy Agency and Iran in Vienna.

So far the Vienna talks have taken place against a backdrop of suspicion and deadlines. The IAEA has put forward a draft agreement under which the Iranians would ship most of their enriched uranium to France and Russia for further processing before the fuel was returned for use in Iran's power plants. And it has given Iran until today to respond.

Whether Tehran will reply as quickly as this, or whether it will continue to procrastinate, is open to question. There are plenty who believe that Iran is determined to develop nuclear weaponry and that it is just using any talks to push back the threat of sanctions against it. But there are also indications that the Tehran regime conscious of the international pressure build-up on it, is genuinely interested in a deal that preserves its right of enrichment but guarantees that it doesn't use the output for weaponry.

With so much turmoil and uncertainty at home, Ayatollah Khamenei – who has always kept the issue under his own control and away from President Ahmadinejad – could well have concluded that he needs the nuclear issue off the table. For Iran the uncrossable line is its right to enrichment. But the agreement proposed by the IAEA would still allow this and give the West the assurances of use that it wants. The one certainty about Iran is that, whatever its intentions, it will play any negotiations to the very last minute. This has always been its tactic and it won't change that, whatever the threats and imposed deadlines.