A senior Saudi Arabian diplomat and member of the ruling royal family has raised the spectre of nuclear conflict in the Middle East if Iran comes close to developing a nuclear weapon.

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 capital 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."

Officials in Riyadh said that Saudi Arabia would reluctantly push ahead with its own civilian nuclear programme. Peaceful use of nuclear power, Turki said, was the right of all nations, guardian.co.uk reported.