Prince Turki al-Faisal, a former Saudi intelligence chief and ambassador to Washington, warned senior Nato military officials that the existence of such a device “would compel Saudi Arabia … to pursue policies which could lead to untold and possibly dramatic consequences”.

He did not state explicitly what these policies would be, but a senior official in Riyadh who is close to the prince said yesterday his message was clear.

“We cannot live in a situation where Iran has nuclear weapons and we don’t. It’s as simple as that,” the official said. “If Iran develops a nuclear weapon, that will be unacceptable to us and we will have to follow suit.”