Singapore’s top leaders are confronting the head of the Singapore Democratic party in a rare courtroom battle over a libel case that could lead to the city-state’s most outspoken opposition group being shut down.

The case is seen as a landmark since it is the first time that Lee Hsien Loong, the prime minister, and his father, Lee Kuan Yew, independent Singapore’s first leader, have been cross-examined in court by political opponents.