The North Korean ambassador to Britain, Hyon Hak-bong, arrived in Beijing on Saturday after a trip to Pyongyang, a diplomatic source said, adding that his trip was unrelated to the recent execution of leader Kim Jong-un's uncle in a dramatic political purge. Hyon, who took up the post in December 2011, was seen arriving at the Beijing airport earlier in the day on an Air Koryo flight from Pyongyang. He didn't respond to questions by a group of journalists.