Donald Trump pulled the US out of the landmark nuclear deal with Iran on Tuesday, vowing to re-impose sanctions on the country and defying pleas from close allies who had called for the agreement to be preserved.

The decision marks a bitter defeat for the US’s top European allies, who have spent months beseeching Mr Trump to stay in a deal that he has denounced as “insane”.

Critics warned it would further endanger stability in the Middle East and have repercussions for major companies that have been doing business with Iran following the 2015 accord.

The 2015 multi-party deal was the key foreign policy achievement of Barack Obama’s presidency, curtailing Iran’s nuclear programme in exchange for limited sanctions relief.

Official inspectors have subsequently declared Tehran to be in compliance with the accord. So have top Trump administration officials, including his new secretary of state Mike Pompeo, who told the Senate in his confirmation hearing last month he had seen no evidence that Iran was failing to comply.