With Osama bin Laden dead, Iran's supreme leader is the biggest threat to global security, Binyamin Netanyahu said in an interview today.

The Israeli Prime Minister told CNN that Ayatollah Ali Khamenei was more of a threat than Iran's President Mahmoud Ahmadinejad.

Speaking on the final day of his visit to London Mr Netanyahu said: "He runs the country and he is infused with fanaticism. If the Iranian regime gets atomic bombs, it will change history.

"The future of the world - the future of the Middle East - is certainly at stake."

However he added that the death of bin Laden was a positive step in the battle against extremism. He said: "When the world's number one terrorist... is brought to justice and eliminated, it tells terrorists everywhere there's a price and you will pay it, and that's good."

Mr Netanyahu's comments follow remarks earlier today by Israel's Defence Minister on Iran's nuclear capabilities.

Ehud Barak told Ha'aretz that should Iran develop a bomb, it would be unlikely to use it on Israel or any of its neighbours. But Mr Barak also warned that Iran's behaviour could not be predicted.