The IAEA has previously assessed that Iran possesses over 60kg of uranium enriched to 60 per cent, which experts say puts the country within reach of one atomic bomb, either by continuing enrichment until the ideal level for a device — which is 90 per cent — or by using some technical workaround.A number of significant technical hurdles would then have to be overcome to construct a bomb small enough to fit on a missile, but the UK said on Monday that Iran was moving quickly on a potential weapon.He said Iran's conduct since September — notably its failure to co-operate with the IAEA, and the expansion of its nuclear programme “for no legitimate civilian purpose” — has reinforced US scepticism “about Iran’s willingness and capability of reaching a deal, and explains why there have been no active negotiations since then”.“We are disappointed that the secretariat, apparently yielding to Russian threats, has not carried out the investigatory mandate this council has given it.”The claims have been denied by Russia, which has argued that there is no mandate for UN officials to travel to Kyiv to investigate the origin of the drones.Tehran has acknowledged that it supplied Moscow with drones but said they were sent before Russia invaded its neighbour in February."