Last December the Israeli deputy ambassador to the UN, Daniel Carmon, was interviewed by the BBC about the Iranian uranium enrichment project. He said: "The americans and British made nuclear weapons with 20 centrifuges: imagine what the Iranians can do with 3,000." In fact, neither the US nor Britain used centrifuges to enrich uranium for their early nuclear weapons. The US primarily used gaseous diffusion in the Manhattan Project during the second world war, while Britain did the same in the early 1950s.