The UK will lead a drive to have Iran referred to the UN Security Council, with the possibility of sanctions being imposed if the newly elected hardline president does not stop uranium enrichment or restart negotiations with Europe and America.
Reflecting the level of concern about Iran's intentions, British foreign secretary Jack Straw was due to meet President Mahmoud Ahmadinejad yesterday on the sidelines of the UN summit to try to resolve the stand-off.
Mr Straw was making a joint approach with French prime minister Dominique de Villepin and German foreign minister Joschka Fischer.
The Europeans have been pursuing the diplomatic route for two years in the face of scepticism from the US and Israel, but negotiations collapsed last month when Tehran restarted its uranium enrichment programme, a step towards achieving a nuclear weapon capability.
Mr Straw is keen to meet Mr Ahmadinejad, one of the hardliners of the regime, to judge if a diplomatic solution is possible. Addressing the UN general assembly, Mr Ahmadinejad said the global body was being undermined by the unilateralism of the US. As he spoke, the US delegation walked out, leaving behind only two note-takers. The US has had no diplomatic ties with Iran since Americans were taken hostage in Tehran two decades ago.
Mr Bush has been lobbying hard to find a majority on the board of the International Atomic Energy Agency (IAEA), the UN atomic watchdog based in Vienna, in favour of referring Iran to the security council. The board meets on Monday.
British officials are drafting a toughly worded resolution to report Tehran to the security council unless the Iranian regime backs down and reinstates its freeze on uranium processing activities.
"It seems we're on track for the security council," a diplomat in Vienna said. "The Iranians are being given every opportunity to climb down. If they don't, it's New York."
Another senior diplomat close to the IAEA who opposes reporting Iran to New York said: "People are running headlong into a brick wall. It's not looking good."
There is no consensus on the 35-member board, but a British government official said last month that the Europeans and the US had a "modest majority", enough to force through referral.