Malcolm Turnbull, Australia’s prime minister, faces an uncertain future after it emerged that the deputy leader Barnaby Joyce is a New Zealand citizen and may be dismissed from parliament.

Mr Joyce, best known internationally for his threat to kill the pet dogs of Johnny Depp and Amber Heard, became the latest victim of the nation’s dual citizenship crisis after revealing he may be a New Zealander via his father, who moved to Australia in 1947.

Mr Joyce was born in Australia in 1967 but - as New Zealand authorities confirmed - he automatically gained citizenship through his father.