The latest report by the International Atomic Energy Agency reveals that Iran is rapidly increasing its stockpile of enriched uranium, which could be rendered into weapons-grade material should Tehran decide to develop a nuclear device.

The agency says that, as of this month, Tehran had amassed 630kg of low enriched uranium hexafluoride, up from 480kg in late August. Analysts say Iran is enriching uranium at such a pace that, by early next year, it could reach break-out capacity – one step away from producing enough fissile material for a crude nuclear bomb.

“They are moving forward, they are not making diplomatic overtures, they are accumulating low enriched uranium,” said Cliff Kupchan, an analyst at the Eurasia Group, a risk consultancy in Washington. “These guys are committed to their nuclear programme: if we didn't know that, they just told us again.”