Andy Burnham as new UK PM faces the defining test for the centre-left. Australia will be watching closely | Tim Soutphommasane

Countering the populist challenge to liberal democracy requires something of a reset The British love a coronation. That’s how the arrival of Andy Burnham into 10 Downing Street is being described in the UK. On Friday, Burnham was “crowned” as Labour leader, after being the only party MP to secure enough nominations following Keir Starmer’s resignation. He is now confirmed as Britain’s prime minister. Australians probably would call this something else: a leadership coup. For months, Burnham…