Experts believe Israeli military planners options are restricted to high risk choices, such as a long range missile bombardment from Israel or a special forces raid involving troops attack facilities on the ground.
The authoritative military journal Jane's Defence Weekly has also cast doubt on Israel's ability to mount a successful operation saying it would face "substantial difficulties"
"The significant distances involved and hardened features of Iran's nuclear facilities make any 'massive surprise' aerial attack a very high-risk operation for Israel to undertake on its own," Jane's concluded in a recent study.
While Israel has the most powerful air force in the Middle East, it would struggle to mount the complex strikes necessary to deal a real blow to Iran's well protected nuclear plants. Senior Israeli officials have warned the country is prepared to take unilateral action to stop Iran acquiring a nuclear bomb.
Israel destroyed Saddam Hussein's Osirak nuclear reactor in 1982 and hit a Syrian reactor in 2007. But to target Iran the airforce would have to carry out numerous strikes with air-to-air refuelling possibly over several days.
"This is not going to be one strike and they are out, not like Syria or Iraq where facilities were not underground, it is much harder than that," said Malcolm Chalmers of the Royal United Services Institute.
"And the Iranians are experts in building reinforced concrete because of their long problems with earthquakes.
"But air strikes could destroy power plants, supply facilities, communications and the centrifuges themselves would be very sensitive to blast. They could do quite a lot of damage which would set back the programme for a period."
Senior British officials have warned that Israel could catch its allies offguard with a strike. "We underestimated the things that the Israelis have done in the past in sheer out-of-the-book daringness," one said.
Options include a daring special forces strike, something Israel has done successfully in the past. A commando raid could be launched from a ship covertly carrying helicopters in the Persian Gulf or from a submarine.
"They have done it before and they are quite capable of doing off the beaten track operations," said a former SAS commander. "I wouldn't say it was impossible but I would be very surprised if they tried to do it, it would be pretty high risk." He added the raid, which would probably involve the equivalent of a squadron around 60 men - would only be able to target one facility, potentially the uranium enrichment site at Fordow which is under a mountain and difficult to hit from the air.
Other methods could include adapting Jericho nuclear missiles with conventional warheads or submarine launched cruise missiles.
But Davis Lewin Political director of HJS, the American aligned think tank, said he was "100 per cent certain" an air attack would succeed without US assistance.
"One reason is that the Israeli Air Force has been cognisant of the need for long range strategic bombing for a long time and is extremely adept at making do with the technology it has in challenging missions."
Israel appears to be involved in a successful covert assassination programme targetting nuclear scientists.
Since 2007 there have been seven attempts on Iranian scientists five of which ended in deaths. There was also a "blast" at a rocket storage facility last November that killed 17 Revolutionary Guards including Gen Hassan Moghaddam, a leading figure in the ballistic programme.
An insight into what Israel might attempt comes from an Israeli security source who said: "Don't think conventional; we are too smart for that." http://www.telegraph.co.uk/news/worldnews/middleeast/israel/9193013/Israel-would-not-be-able-to-destroy-Irans-nuclear-programme-with-pre-emptive-air-strike.html
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