The nuclear brinkmanship between Iran and the West is expected to step up a gear amid predictions that Tehran is about to announce that it has begun industrial-scale production of enriched uranium. Iran has started installing about 3,000 centrifuges, the machines that can turn uranium into fuel for nuclear reactors or bombs, at a huge plant in Natanz - a prime target if the US or Israel conclude that there is no other way to stop Iran acquiring the bomb.For all Iran's bluster, the International Atomic Energy Agency (IAEA) believes that technological setbacks mean it is still some years away from being able to produce enriched uranium on a big enough scale. But fear of imminent bombing of Iran's nuclear facilities is so strong that Robert Gates, the new US Defence Secretary, said at the weekend: "We are not planning for a war with Iran."