By Madeline Chambers
LONDON (Reuters) - Iran, threatened with referral to the U.N. Security Council over its atomic ambitions, could develop bomb-making capability in as little as five years but a 15-year timeframe is more likely, a think tank said on Tuesday.
Iran resumed sensitive nuclear work last month, bringing two years of talks about its atomic programme with the European Union trio of Britain, France and Germany close to collapse.
The United States and European Union suspect Iran wants to use a civilian nuclear programme as a cover for developing atomic weapons, a charge Tehran denies.
"If Iran threw caution to the wind and sought a nuclear weapon capability as quickly as possible, without regard for international reaction, it might be able to produce enough highly enriched uranium for a single nuclear weapon by the end of this decade," said John Chipman, director of London's International Institute for Strategic Studies.
He said technical problems could prolong the process and that given international pressure, the Islamic state was more likely to try to accumulate the capability over 10 to 15 years.
The evaluation by the influential think tank comes two weeks before the U.N. atomic watchdog (IAEA) will discuss whether to send Iran to the Security Council, possibly prompting sanctions.
The assessment is in line with British estimates, although U.S. intelligence reports have been more conservative, with a study last month putting the date for a bomb at 2015.
"Our assessment is technical," Gary Samore, editor of the IISS report, told reporters.
"The most interesting discussion is about political calculations and how Iran weighs the risks and benefits of acquiring nuclear weapons capability."
Samore said Iran appeared to be less worried about possible U.S. military action than two years ago, partly due to what he described as "the mess" in Iraq.
Washington has not ruled out using force to stop Iran's nuclear programme although its main ally Britain has said such action would be inconceivable.
Samore said the think tank believed Washington would have a serious debate about military strikes if the Security Council failed to persuade Iran to freeze its programme.
It is unclear whether the Europeans and the United States have sufficient support to reach consensus for Security Council referral at the International Atomic Energy Agency (IAEA). Russia opposes the idea and China's intentions are unclear.
"I don't see any choice. Since Iran has broken the political deal it reached with the IAEA board of governors, I think the board has no choice but to send it to New York," Samore said, referring to the U.N.'s headquarters.
"Whether it is by consensus or by vote, either way it ends up in New York."
