A Hong Kong secondary school principal filmed swearing at security guards during a student trip to Singapore has resigned and apologised for his failure to “lead by example”. Lee Cheuk‑hing tendered his resignation on Thursday as principal of San Wui Commercial Society Secondary School in Tuen Mun, school manager Edmund Wong Chun‑sek confirmed. Wong, a former lawmaker, said the school’s board of directors would have to meet to decide whether to accept the resignation, given the many factors...