Richard Beeston, Diplomatic Editor of The Times, examines the implications of Iran's removal of IAEA seals from its Natanz uranium enrichment facility:

How serious is this latest move by the Iranians? Is it really just for 'research purposes'?

This is a very serious move. The research in question is located at Iran's Natanz facility in central Iran. The site is the main centre of Iran's uranium enrichment, the key process to mastering the fuel cycle for a nuclear reactor. The technology can also be used to produce highly enriched uranium: the key element for an atomic bomb.

While the Iranians insist that they are not reactivating enrichment, clearly research into this field involving centrifuges will help them master the technology. Once they have done that they will have reached "the point of no return". That is why everyone is so concerned about the move.

Will the UN Security Council have to act or can negotiations still continue?

The next step being proposed by the British and other Western nations is convening an emergency meeting of the 35-member International Atomic Energy Agency (IAEA) in Vienna. This is the body responsible for overseeing nuclear activity around the globe. It has already voiced concern about Iran's actions and a further statement by Mohamad ElBaradei, the IAEA secretary general, is due later today.

Britain, America and most Western nations have reached the point where they believe mediation is useless and Iran must be referred to the UN Security Council. For that they will need a simple majority of the 35 members. This will take some diplomatic arm-twisting, but the Americans believe that there is a majority. President Mahmoud Ahmadinejad's inflammatory remarks threatening to "wipe Israel off the map" have damaged the Iranian cause. If Iran is referred, then the UN Security Council would have the power to impose punitive sanctions and other measures on Iran.

What, or who, can bring Tehran back to the table?

The last viable option on the table appears to be an offer by Russia to deliver enriched uranium as fuel for the Iranian nuclear programme. So far Iran has rejected the proposal, but it also knows that if it alienates Russia then it will lose its last potential significant ally on the international stage. If not there is the real chance of sanctions. While this would certainly damage Iran's economy, which relies heavily on Europe and other major trading partners, some in Tehran believe that the high oil price and Iran's large and porous borders would make any meaningful sanctions unrealistic.

Is this a further sign that President Ahminejad does not care what international opinion thinks?

To a large extent, yes. He has made it very clear since he came to power five months ago that he intends to uphold the spirit and letter of the Iranian Revolution led by Ayatollah Khomeini in 1979. He has described previous attempts to improve relations with Europe as a "failure". He is intent on making Iran's policies very clear. He has removed an entire cadre of sophisticated, and some would say Westernised senior diplomats, he has replaced other key government officials with those who share his hardline ideology. He has repeatedly threatened Israel and Iran's other enemies. He does not seem to care very much what the world thinks of him.

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