South Korea built the Cheongung-II to stop North Korean missiles. Now the system is stopping Iranian ones – and in doing so, has turned Seoul into one of the most sought-after defence suppliers on the planet. The medium-range surface-to-air missile system, also known as the KM-SAM Block II, has scored a reported interception rate of 96 per cent against Iranian missiles fired at the United Arab Emirates. It was a combat debut that rivalled, and in some cases exceeded, the performance of the US...