Iran's nuclear ambitions could plunge the Middle East into "a new Cold War", the UK foreign secretary has warned.

Iran unveiled developments in its nuclear programme earlier this week

William Hague told the Daily Telegraphother nations in the region would want to develop nuclear weapons if Iran did.

Without "the safety mechanisms" of the US-USSR rivalry, Mr Hague said it would be "a disaster in world affairs".

But ex-UK diplomat Sir Richard Dalton said Iran was not "rushing towards a nuclear weapon". Tehran insists its programme is for energy purposes.

The West suspects Iran wants to develop nuclear weapons.

Mr Hague told the newspaper there was a "crisis coming down the tracks".

"If [the Iranians] obtain nuclear weapons capability, then I think other nations across the Middle East will want to develop nuclear weapons.

"And so, the most serious round of nuclear proliferation since nuclear weapons were invented would have begun with all the destabilising effects in the Middle East."

'Enormous downsides'

Mr Hague's comments come amid heightened tensions in the Middle East, with Israel accusing Iran of masterminding attacks on its embassies in India, Thailand and Georgia. Iran denies the allegations.

It blames Israel and the US for the assassination of several Iranian nuclear scientists in recent years, allegations they deny.

Speaking earlier this month, US President Barack Obama emphasised that Israel and the US were working in "unison" to counter Iran.

However, some commentators have suggested that behind the scenes Washington is deeply alarmed by reports that Israel may strike Iran as early as April. US Defence Secretary Leon Panetta reportedly said there was a strong likelihood of such an offensive.

Mr Hague told the Telegraph that Britain has urged Israel not to strike: "We support a twin-track strategy of sanctions and pressure and negotiations on the other hand.

"All options must remain on the table" but a military attack would have "enormous downsides", he said.

Shashank Joshi, of defence think tank the Royal United Services Institute, told the BBC the West's fears could be unfounded.

"If we could live with nuclear weapons in the hands of totalitarian, genocidal states like Stalin's Russia or Mao's China, Iran in contrast - whatever its repulsive internal policies and adventurism abroad - is far more rational," he said.

Mr Joshi said Iran may not be actively pursuing the creation of nuclear weapons but leaving the option open.

"If they feel their regime is under existential threat, if they feel they face a Libya-like situation, they would have the option of building a bomb."

Answer questions

Sir Richard, a former UK ambassador to Iran, said: "There are many signs, as reported by the International Atomic Energy Agency, that some research and development relevant to the development of nuclear weapons may still be going on.

"But it is wrong to say that Iran is rushing towards having a nuclear weapon.

"Indeed, the analysis published to the United States Congress by the top intelligence assessors there indicates that Iran has not taken a decision to have a nuclear weapon.

"But it is right that the IAEA should press Iran on behalf of the international community to answer fully questions about what it has been up to in the past and what it may still be doing in the present."

Shadow foreign secretary Douglas Alexander said: "Instead of raising the rhetoric, the government should be focused on redoubling their efforts to increase the diplomatic pressure on Iran and find a peaceful solution to the issue."

Meanwhile, Iranian warships have entered the Mediterranean Sea for only the second time since the 1979 revolution.

The destroyer Shahid Qandi and its supply vessel Kharg have passed through the Suez Canal but their destination remains unclear.

On Friday, the US and European Union expressed optimism at the possibility of a resumption of talks with Iran.

US Secretary of State Hillary Clinton said a letter from Iran to the US and its allies was "one we have been waiting for".

However, our correspondent said that while Iran had often offered to talk, Western diplomats complained it would steer discussions away from its nuclear programme to leave "parallel monologues" rather than negotiations.

Talks between Iran and six world powers - the US, UK, France, Germany, Russia and China - on Tehran's nuclear programme collapsed a year ago.

In recent months, Western countries have stepped up pressure on Iran over the nuclear issue, with the EU and US both introducing wide-ranging sanctions on the country.

On Wednesday, Iran staged an elaborate ceremony to unveil new developments in its nuclear programme, It said it had used domestically-made nuclear fuel in a reactor for the first time.

There are a number of sites at the centre of concerns over Iran's nuclear programme.

Worrying, but I'm more concerned that Ahmadinejad will succeed in bringing Members Only jackets back into fashion.

But isn't Iran, like, a desert?

I say we nuke them before they nuke us!

cold war with what,a broke USA and europe economy?

even if iran had nukes,they jst couldn't reach USA

ever seen a world map?

if israel nukes iran which it can't as it doesn't have the balls to do so,it will unite every muslim in the world

that time they will not care how many die,israel will be wiped of the earth.

thats why they are pushing USA to do so.which will start WW3

Iran is banking on the fact that the president of the United States is a "pussy" (in the Team America World Police sense), the political climate in the house and senate is heavily partisan, and the European economy is in crisis to do whatever they want because no one will stand against them.

I say let them handle it on their own.

Man you guys shore seem eager to blow countries up ... I know it's easy to write random stuff on the internet but seriously some people should try imagining the amount of individuals present in this planet of ours, each one with their own identity, dreams, beliefs, etc... before setting of in a quest of annihilation.Like a professor of mine used to say, "before tackling a problem you should try different hats on", the hats in this case being different points of view.

And letting fear dominate you train of thoughts isn't really what I would call a informed decision.

About nuclear weapons, witch I completely hate and truly wish that this technology had never been invented, I think that these countries like iran feel the need to procure them not just because some people live with this concept off killing the infidels but because they as a country probably feel the need to level the plain field.
At least this is how I imagine it, they probably don't intend to use said "nuclear weapons" they intend to have them as a means to tell other countries, one in particular, to stop meddling in their internal affairs.

Off course I think no one should have nuclear weaponry, but then how does it work when some do and some don't.

I'll believe this when we start seeing the Iranians as the bad guys in every single action or spy movie and videogame that comes out over the next decade or so.

It's been more than 2 decades after the Cold War ended, and we're still seeing Russians as the quintessential villains. Why???