Iran’s first nuclear power plant, which Russia is building in the town of Bushehr, will not be completed before 2008, Russia’s top nuclear official said Wednesday.

Iran’s nuclear programme is facing such severe technical difficulties that it could take four years to produce enough weapons-grade uranium for one bomb and eight years to deploy an operational nuclear weapon, experts say.

President Mahmoud Ahmadinejad’s announcement on April 9 that uranium enrichment on an “industrial scale” had begun was “misleading” and the time-scale for success is likely to be longer than early estimates suggested.