The United Nations' nuclear watchdog has said that North Korea has made “very serious” progress in its ability to produce nuclear weapons. This comes at a time when the topic of nuclear warfare is rife amid ongoing tensions in the Middle East over what the US says is a result of Iranian nuclear capabilities. North Korea is believed to have assembled about 50 nuclear warheads , but some experts are sceptical of its claims that it is able to miniaturise them to be attached to long-range ballistic