What’s not to like? The deal reached between Iran and six world powers in July is a major diplomatic breakthrough. In exchange for Tehran halting its nuclear weapons programme, the West will lift the sanctions that have been crippling Iran’s economy for the last decade. The deal was hailed by President Obama as ‘a historic understanding’ and met with cheers of approval from around the world. Of course, the agreement doesn’t guarantee that Iran will never get the bomb some time in the future. But its supporters argue that in a complex world it’s the best option going. There will be no pre-emptive strike on Iran’s nuclear facilities for at least 10 years. The freeing up of over £100 billion of frozen assets will increase Iran’s stability, and the improved communication and trade between Iran and other countries will strengthen the hand of those Iranians who want their nation to be part of the modern world. The deal is a major step towards making the world a safer place.

That’s the line of those who support the deal. But to others, including Israel’s prime minister Binyamin Netanyahu, it’s not so much a historic understanding as a terrifying historic mistake. The Iranians, they say, have a track record of wily negotiating. Once the agreement’s restrictions expire in around 2025, what is there to stop the mullahs cranking up their nuclear programme and producing the bomb? In the meantime, relaxing sanctions will allow the Tehran to channel ever more funds to murderous regimes such as Assad’s Syria, and the terrorist organisations Hamas and Hezbollah. Furthermore, by cosying up to the Shiite Iranians, the West risks alienating its Sunni allies in the Middle East and leaving Israel feeling even more dangerously exposed.

Will the deal avert war and give moderate Iranians the time they need to bring their country in from the cold? Or will it do no more than put a hold on Iran’s nuclear ambitions and allow the mullahs to ramp up their dangerous meddling in the region?  Alan Dershowitz, one of America’s most formidable and celebrated lawyers, and Emily Landau, one of Israel’s top nuclear proliferation experts, went head to head with senior politicians Norman Lamont and Jack Straw, both impassioned advocates of rapprochement with Iran.