DONALD TRUMP’S cheerleaders and assorted wishful thinkers suggest that the US president’s intemperate decision to abandon the Iran nuclear agreement will usher in speedy negotiation of another better deal.

The Joint Comprehensive Plan of Action (JCPOA) signed by the five permanent members of the UN security council, plus Germany and Iran, in 2015 took hard negotiations over a substantial timescale to secure agreement.

It provides for gradual removal of damaging economic sanctions against Tehran in return for Iran’s uranium enrichment programme being wound down.