Professor Dershowitz said he believed President Barack Obama had broken his promise when he vowed that Iran would not achieve nuclear weapons, he told delegates at the event on Saturday.

He said: “We stand on the precipice of a tragic mistake relating to Iran that could have cataclysmic effects on world peace.

“The deal that we have put on the table for Iran is a bad deal. It does not prevent Iran from becoming a nuclear power ultimately and a nuclear threshold power very very quickly.

“It says nothing about Iran’s ability to develop Intercontinental ballistic missile which threaten not only the Middle East but Europe and United States as well.

“It doesn’t prevent Iran from developing nuclear triggers which have no peace time use and can only be used to create weapons of mass destruction. It’s a bad deal. It’s a bad deal because it does not permanently tell Iran that it can’t develop nuclear weapons.”

The deal now proposed has a ‘sunset provision’, meaning it only delays Iran’s quest to acquire a nuclear bomb, Professor Dershowitz said.

He added: “Iran, because it will become a nuclear power, will have the ability to bring people under its influence because the inevitability is that it will be a nuclear power and most important for us in this room, it will guarantee continued repression by the mullahs of the people of Iran and of you and of your friends and of your relatives. Repression is guaranteed, if there is going to be the potential for nuclear weapon.

“What is the promise made directly to me in the Oval Office? With the president looking right into the eye and said ‘Take my word, Iran, will not develop nuclear weapon’. That promise is in the process of being broken.

“Iran and the mullahs are not rational calculators … This is a suicide nation controlled by suicidal leaders. As one leader recently said, if Iran develops a nuclear weapons and bombs Tel Aviv, it will kill three million Israelis. Israel retaliates, bombs Tehran and kills 20 million Muslims then the trade off will be worth it.

Because it will destroy the state of Israel and Islam and Iran will still survive. You can’t trust people with that kind of apocalyptic view with weapons of mass destruction.”

He added: “Mr President, as your friend, I don’t want you to be remembered by history as the man who failed to recognize the greatest danger of the 21st century – a nuclear armed Iran.”