Telegraph, UK, Sunday, 12/02/2006:

Iran has drawn up designs for a deep underground tunnel with remote-controlled heat and pressure sensors as part of what Western intelligence officials believe are preparations for a secret atomic test.

The plans, which American and British intelligence conclude are genuine after studying them on a laptop computer smuggled out of Iran by a defector, appear to be the latest evidence that Teheran is conducting a clandestine nuclear weapons programme.

	The Natanz enrichment facility

The existence of the sophisticated sketches for a 400-metre long subterranean test shaft was made public last week in The Washington Post. The welter of documents and disclosures provides what Western governments believe is an overwhelming circumstantial case that Iran is seeking an "Islamic bomb".

Washington and London won International Atomic Energy Agency (IAEA) support last weekend for Iran to be reported to the United Nations Security Council, after the clerical regime resumed banned centrifuge research work at its Natanz uranium-enrichment plant.

Publicly, even American hawks such as Vice-President Dick Cheney are backing the diplomatic track to resolve the showdown over Iran's nuclear programme, which Teheran claims is for peaceful energy purposes. But the Sunday Telegraph has learnt from a senior Pentagon adviser that, as the crisis deepened in recent months, military strategists have been updating plans for "last-resort" military strikes on Iranian nuclear sites. The raids would be ordered if President George W Bush is advised that they are the only remaining option to prevent the Islamic republic from acquiring atomic weapons.

Jack Straw, the Foreign Secretary, has consistently made clear that Britain opposes a military solution. He fears that even the threat of bombing will sabotage any hope of securing a united international diplomatic front against Teheran - as well as again splitting the Labour Party. British diplomats highlight the chaos that Iran, if attacked, could unleash in the region through its Shia surrogates in Iraq, Hizbollah in Lebanon and Hamas in the Palestinian territories.

A high-powered British diplomatic delegation visited Washington last week to discuss tactics with Nicholas Burns, the State Department's number three. They want to increase co-operation with Iranian exiles and make better use of satellite television channels and the internet to spread the message inside Iran that the West's opposition to Teheran's nuclear programme is not an imperialist anti-Islamic plot, as the mullahs claim.

Britain is hoping that the threat of action by the Security Council, including possible financial sanctions, will expose differences within the regime on how far to push its game of nuclear brinkmanship. But there is a growing belief in Washington that it will be impossible to win the required Chinese and Russian support at the UN for any significant measures that might inhibit Iran's nuclear ambitions.

The review of the Pentagon's contingency plans follows the stream of recent discoveries of Iran's secret nuclear operations and the virulent rhetoric of President Mahmoud Ahmadinejad since he was elected last year. Iran is still thought to be anywhere between three and 10 years away from physically producing a nuclear weapon. But the West and Israel believe the "point of no return" - when Iran's scientists acquire the technological know-how and experience to make an atomic bomb - could be reached much sooner.

The Pentagon adviser told the this newspaper: "We will have reached the point of no return in the next couple of years. If diplomacy hasn't worked by then, Iran will be a long way down the line to acquiring a nuclear weapon. We're talking about choosing the least bad of a series of bad options. President Bush will also be nearing the end of his term and have to decide if he trusts this issue to another administration or wants to use the B2s." In a separate interview, Richard Perle, a senior defence official at the time of the Iraq war and who maintains close links to the military, said that 12 B2 bombers, each carrying dozens of precision-guided weapons, could deliver a serious blow to Iran's nuclear ambitions.

"If the President were faced with the choice between Iran crossing the line to become a nuclear weapon state and using force to destroy or significantly delay that prospect, then I believe he would use force," Mr Perle said. "That decision will be made at the last moment but there is certainly strong contingency planning for that. I think the decision-making elite in Washington would back Mr Bush if that was seen to be his only choice."

Iran has been preparing by strengthening air defence systems and building tunnels intended to hide atomic material and facilities from a bombing campaign, Jane's Defence Weekly reported this month.

The regime has spread its nuclear programme across several sites, some of them underground, after drawing lessons from the 1981 Israeli air strike that wiped out Saddam Hussein's efforts to produce an Iraqi plutonium bomb at Osirak. But United States military strategists believe that by targeting certain key "bottleneck" facilities - probably the Natanz uranium-enrichment site, the Isfahan conversion plant and the Arak heavy water reactor - they could hobble the whole programme for years.

"There may well be secret sites out there but a nuclear programme is not that easy to hide," said Dan Goure, a Pentagon consultant and vice-president of the Lexington Institute defence think-tank. "You need large sites for uranium enrichment and manufacturing plutonium. It's not like a biological or chemical warfare programme: you cannot conduct research in a Petri dish."

Mr Perle and Dr Goure believe that America is better equipped to carry out the attacks than Israel, whose F15s and F16s would encounter refuelling problems. In a further signal that if strikes were required the US would prefer to carry them out, Mr Bush said last week that America would "rise to Israel's defence" if Iran threatened it.