South Korea has imposed heavy security as south-east Asian leaders begin arriving for a summit. It follows a number of missile tests by North Korea which have left nerves frayed across the region. A surface-to-air missile has been positioned outside the venue of the meeting on the island of Jeju, aimed towards the north. Around five thousand police officers have been drafted in for the event and special vehicles capable of analysing sarin gas have been deployed nearby. The summit gets underway tomorrow.