British Prime Minister David Cameron has urged the international community to show “courage” and allow the sanctions, which have been imposed on Iran, to take effect.

Speaking at a United Jewish Israel Appeal in London he said that this was not the time for Israel to take military action against Iran.

"I have said to Prime Minister Netanyahu that now is not the time for Israel to resort to military action.

"Beyond the unpredictable dangers inherent in any conflict, the other reason is this: at the very moment when the regime faces unprecedented pressure and the people are on the streets; and when Iran's only real ally in Syria is losing his grip on power, a foreign military strike is exactly the chance the regime would look for to unite his people against a foreign enemy.

"We shouldn't give them that chance. We need the courage to give these sanctions time to work."

Mr Cameron said that the “relentless” sanctions are starting to have an impact on Tehran.

He pointed out that as well as slowing the nuclear programme, Iran’s oil exports have dropped by 45% and inflation has soared.

"Most significantly, there are signs that the Iranian people are beginning to question the regime's strategy with even pro-regime groups protesting at the actions of the government.

"It's mind boggling that the leaders of a nation so rich in oil have succeeded in turning their country into a banana republic desperately trying to put rockets into space while their people suffer.

"The Iranian regime is under unprecedented pressure and faces an acute dilemma. They are leading their people to global isolation and an economic collapse. And they know it."

But he stressed that all options are open if Iran makes the “wrong choice”.

"In the long term, if Iran makes the wrong choice, nothing is off the table. A nuclear armed Iran is a threat to Israel. And a threat to the world. And this country will work unwaveringly to prevent that from happening."