 He was also a member of the Singapore delegation in the Rahman–Marshall talks in 1955.In April 1956 Koon-Teck, representing the Liberal Socialist party accompanied Chief Minister David Marshall to London for the first Malayan Independence or Merdeka Constitutional Talks at Lancaster House.Included in the delegation were Minister for Labour Lim Yew-Hock, Minister for Local Government Abdul Hamid bin Haji Jumat, Minister for Health A. J. Braga, Minister for Commerce and Industry J. M. Jumabhoy, Wong Foo-Nam and Seah Peng-Chuan (other members of the coalition government), WilliamTan, Lim Choon Mong and Lim Cher Keng (Liberal Socialists), Lee Kuan Yew and Lim Chin Siong (People's Action Party).