Within the next 12 months, the Americans or the Israelis, possibly both, are likely to launch military strikes aimed at crippling Iran’s nuclear ambitions. Those strikes may come sooner rather than later. And they will probably be nuclear.

Israeli military analysts say intervention is essential before Iran’s scientists are able to complete the nuclear cycle — some time during 2007 — and start producing weapons-grade uranium. President Ahmadinejad himself has boasted of ‘mastering the fuel cycle’ during the Ten-Day Dawn festival in early February when Iranians mark the anniversary of the 1979 Islamic Revolution. At that moment, Iran will have passed what the Israelis call ‘the point of no return’, when enriched uranium can be extracted, stored far from nuclear facilities and be virtually impossible to find.

It will be another two years, according to intelligence estimates, before Iran is able to accumulate sufficient weapons-grade uranium to make a nuclear bomb. Meanwhile, smaller amounts could be doled out to a multiplicity of Iranian-supported terrorist groups, including Hamas, Hezbollah and Islamic Jihad, to make ‘dirty’ bombs which combine a conventional explosive with radioactive material, such as small amounts of enriched uranium. Just last week the Home Office confirmed that there was to be an increase in the number of police officers trained to deal with ‘dirty’ bombs.

Only the Americans and the Israelis are willing and able to stop the Iranians before they pass the critical enrichment threshold. The United States is this month reported to be deploying an additional aircraft carrier and accompanying strike group to join its existing fleet of cruisers, destroyers and submarines in the Gulf. While senior American officials caution that increased naval power in the region should not be interpreted as preparations for an attack, they acknowledge that their ability to strike at Iran will be enhanced.

But Washington may be too bruised and traumatised by its Iraqi imbroglio to open a fresh front in the Middle East. That leaves Israel. And, after President Ahmadinejad’s repeated calls to ‘wipe Israel off the map’ and his Holocaust-denial conference in Tehran last month, Israel’s motivation is sky-high.

‘We are talking here about a threat to the survival of the state of Israel, and on that issue there can be no compromise,’ a senior Israeli source told me. ‘We are the product of the Holocaust in Europe and we will do everything — I mean everything — to prevent another holocaust occurring in Israel. If the Americans do not act, then we will act. And that moment,’ the source added, ‘might be closer than people dare to imagine.’

Last month, Israel’s Prime Minister, Ehud Olmert, underscored the point when the German news weekly Der Spiegel invited him to rule out the possibility of a military strike against Iran. His response was curt: ‘I rule nothing out.’ The Israelis will not, of course, describe the nature of possible military action, but there is a broad consensus that there is not a golden bullet: it is now impossible to prevent Iran from ultimately acquiring nuclear weapons if that remains their determined objective. Whatever havoc may be caused to their facilities, Iran has the scientists, engineers, know-how and funds to start again.

The best-case scenario is that Iran’s nuclear progress can be degraded until an effective anti-missile umbrella is developed or, perhaps, until a new Iranian leadership emerges that is less susceptible to notions of Islamic conquest. The aim of military strikes will therefore be to disrupt and delay Iran’s activities by destroying key links in its nuclear chain.

The route to Iran’s nuclear ambitions — and the prime targets for attack — run through four main nuclear facilities: at Bushehr, where a nuclear power plant is being built; at Natanz, where a major fuel-enrichment plant is located; at Arak, where a heavy-water plant has been inaugurated for producing weapons-grade plutonium; at Isfahan, where 3,000 scientists are engaged in a broad spectrum of nuclear-related activities, from co-ordinating the design of nuclear weapons to producing UF6 gas, the feedstock for centrifuge enrichment in uranium-conversion facilities.

While Iran is estimated to have up to 70 sites that are dedicated to nuclear development, American analysts say it could take just 15 accurate hits to retard the programme and delay development of the Iranian bomb for years. The problem here is that conventional American weapons can penetrate up to 30 feet of hardened materials or 100 feet of earth, but some of the Iranian facilities are reportedly buried at depths of up to 200 feet. That problem is compounded by the fact that Iran has constructed most of its facilities under alternating layers of earth and cement that have been specifically designed to absorb the impact of deep-penetration bombs.

The centrifuges are the essential ingredient in the enrichment process. They are also the weakest link and the priority target. These instruments are highly sensitive to the earth’s movement: if the environment is unstable they will become distorted and cease functioning. Satellite images of the Natanz facility indicate that two large centrifuge facilities are buried under a mix of reinforced concrete and soil at a depth of at least 75 feet, beyond the range of America’s bombs.

But there is a way of disrupting the centrifuges by simulating earth tremors through a nuclear strike. The neutron bomb, says one European source, might have been designed specifically for the purpose. This ‘clean’ atomic device emits huge quantities of high-energy neutrons which are capable of penetrating the toughest tank armour, destroying all biological tissue and electronic systems within its range.

The neutron bomb has two advantages: first, the impact of its destructive force is limited to a radius of just a few hundred yards; second, it leaves virtually no radioactive fall-out. Israel’s own nuclear programme, which remains shrouded in ambiguity, is said to include a substantial stockpile of neutron bombs. It is now widely assumed that a mysterious double flash detected by an American satellite over the Indian Ocean in September 1979 was caused by the test of a three-kiloton Israeli neutron bomb.

In addition to warheads that can make the earth move, Israel also has a family of highly accurate delivery systems — missiles that can be launched from land, sea or air — that are capable of delivering a nuclear payload. The distance between Israel and Iran makes an air strike highly problematic, but Israel does have other options: it can, for example, launch a strike against the Iranian facilities by one or more of its three Dolphin-class submarines that have been acquired from Germany over the past eight years. Officials from both the Pentagon and State Department have reported that unarmed, nuclear-capable missiles were test-fired by an Israeli submarine in the Mediterranean in 2000.

A military strike by the United States or Israel will be the last resort, a sign that diplomacy has failed and that Iran is about to turn on the tap of weapons-grade material. In recent years, and with increasing urgency over the past 12 months, an alphabet soup of multilateral organisations — the industrialised world’s G8, Europe’s EU3 and the UN’s P6 — have huffed and puffed while Iran’s skilful negotiators ran rings around the infidels who were sent to buy them off. Hossein Mousavian, Iran’s delegate to the International Atomic Energy Agency, admitted as much in an interview on Iranian television. Iran, he said, had used its protracted negotiations with the EU3 — Britain, France and Germany — to ‘buy time’ while it completed its nuclear facilities.

Last month, the UN Security Council finally adopted a resolution which imposes a sanctions-lite regime on Iran. Mr Ahmadinejad’s electoral setback just a few days earlier clearly affected neither the defiant substance nor the menacing style of his response to the UN vote. Iran, he declared, has started installing 3,000 new centrifuges. Whether the West likes it or not, he continued, Iran is a nuclear state and ‘it is in their interests to live alongside Iran’. Sanctions, he added, would not harm the Iranian people, but, he warned, ‘the signatories of this resolution ...will soon regret this superficial and trivial move’.

Tehran’s official insistence that its nuclear programme is intended strictly for civilian use is universally discounted by military experts. Why, they ask, does one of the world’s richest oil and gas states need to develop more complex and more expensive nuclear power? Why, if its intentions are peaceful, did Iran deliberately deceive the UN nuclear inspectors for years? Why is Iran seeking to hide its facilities underground? Not least, why is it acquiring thousands of centrifuges capable of enriching uranium to produce weapons-grade material?

Iran’s nuclear programme has also, significantly, been accompanied by a vigorous drive to develop appropriate delivery systems. Already, the entire Middle East and parts of southern Europe are within range of the Iranian missiles. By the end of the decade their reach will have been extended to cover all of Europe. They will then be approaching global range.

Israel is not the only state in the region with cause for concern about the prospect of a nuclear Iran. Intra-Islamic fault lines are becoming more sharply defined even as the fog of Iraq’s internecine conflict grows thicker. Saudi Arabia, centre of gravity of the Sunni world, is particularly wary about the rise of Shia Iran as the hegemonic power of the Gulf — and, perhaps, beyond.

Officials from Saudi Arabia and the smaller Gulf states of Kuwait, Bahrain, Oman, Qatar and the United Arab Emirates are already reported to be exploring the prospect of creating a joint nuclear programme. Egypt will not be far behind in its quest for nuclear capability, nor will Turkey.

A successful military strike on Iran’s nuclear facilities, by America or Israel, will be cause for private celebrations throughout the Middle East, though public expressions of diplomatic outrage will predictably be as ferocious as those that followed Israel’s pre-emptive strike which destroyed Saddam Hussein’s nuclear reactor at Osirak in 1981.

Iran has been emboldened by its recent successes in Iraq and Lebanon. Without firing a single shot or suffering a single casualty, Iran has emerged as the most influential player in Iraq, America not excepted. ‘The Iranians can look forward to many years when they will be able to regard Iraq as their backyard,’ a senior Iraqi political source told me last week. And, through its Syrian ally and Hezbollah proxy, Iran has also become the dominant force in Lebanon.

Beyond Iraq and Lebanon, Iran is seeking to use its economic muscle to build influence in the Muslim world. But it remains hampered by two intrinsic disabilities: first, it is a Shiite state in a largely Sunni environment; second, it is a non-Arab state in a largely Arab world. To overcome these handicaps, Iran has to prove its credentials, and it can achieve this not only by acquiring the ultimate weapon, but also by being first among equals in its hostility to the Jewish state, the totemic issue of the entire Islamic world.

Two niggling questions remain unanswered: why are the Iranians so brazenly flaunting their nuclear programme? And why are they so obviously goading the Israelis by issuing a flurry of existential threats? They seem to be deliberately provoking an Israeli attack. But that could be precisely what they want to achieve.

In addition to Iran’s indigenous nuclear programme, there have been reports that it has bought several nuclear bombs ‘off the shelf’ from rogue scientists in the former Soviet Union. So, for all the fuss about its nuclear programme, Iran might already have several tactical nuclear weapons stuffed in its armoury.

If Israel is drawn into a pre-emptive strike, the Iranians might reckon that the international community will judge an Iranian nuclear response to be proportionate, even justifiable. With their political compass fixed at the dangerous intersection of ideological fervour and religious zealotry, the mullahs of Tehran could be calculating that such an outcome will succeed in both burnishing their Islamic credentials and realising their cosmic dream of dominance.