Last Friday at 1.02pm, Australians were forced to endure a depressingly familiar sight: an MP emerged from a secret party meeting in Canberra to announce that the nation had a new prime minister.

Despite being the preferred Liberal leader of fewer than 10pc of Australians, Scott Morrison, a 50-year-old staunch conservative and evangelical Christian, had won a party-room ballot to replace Malcolm Turnbull, a 63-year-old former investment banker and self-made millionaire.

A survey in April found that almost half of Australians had never heard of Mr Morrison, who has just become the sixth prime minister in eight years.

“Who‘s Next?” asked the front page of the Northern Territory News.

“It‘s a bloody joke,” said a pedestrian interviewed by SBS News.

The ousting of Mr Turnbull, a former Rhodes scholar who led the push for a republic in the1990s, marks a worrying trend in Australia that now seems difficult to stop.

Each of Australia‘s last four leaders has been toppled by their parties.

Labor‘s Kevin Rudd was ousted in 2010 by Julia Gillard, who was ousted in 2013 by Mr Rudd, and the Liberal leader Tony Abbott was toppled in 2015 by Mr Turnbull, who was ousted at lunchtime last Friday in favour of Mr Morrison. No Australian leader has served a full term since John Howard after the 2004 election.

“Australia has cemented its reputation as the coup capital of the world,” said commentator Troy Bramston in The Australian.

“The voters look on with horror as the deception, treachery and killings become routine. They know how the pantomime works.”

This revolving-door leadership has made the nation a laughing stock and the chaos this week prompted fresh questions about the causes of this bizarre Australian phenomenon.

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In recent decades, the nation‘s MPs have increasingly entered politics after careers as political aides or lobbyists. With little experience outside politics, they are motivated by short-term ambitions and are liable to be spooked by a poor run of opinion polls, now conducted with ever greater frequency.

In Australia (which apes the British system operating in Westminster) the party‘s MPs have traditionally elected their own leader.

But this makes it easy for a small number of disgruntled MPs to demand a leadership ballot and produce instant instability. Australia‘s Labor party now allows rank-and-file members a say in electing leaders – and last week‘s events have prompted calls for the Liberal party to do the same.

Jonathon Duniam, a Liberal MP, said yesterday: “Only two [MPs] can bring about a leadership spill, and as we‘ve seen last week, once the action is put in motion, it can rarely be stopped.”

But the deeper problem appears to be that Australia‘s coups have proven self-perpetuating: they produce unelected prime ministers, who lack a mandate from the public and lead a party that will inevitably be riven by recrimination and internal feuds.

Mr Turnbull was ousted this week following a rebellion led by a group of right-wing MPs – “wreckers”, he understandably called them – who have long regarded him as too progressive.

The most vocal of his critics was Mr Abbott, a monarchist and long-term foe of Mr Turnbull who has spent the past three years seeking to avenge his own ugly removal.

The rebels were supported by a group of right-wing pundits and so-called “shock jocks” – deliberately provocative radio hosts. Many of his fiercest critics were on Sky News, a cable television channel owned by Rupert Murdoch, which broadcasts news during the day but hands over to mostly right-wing pundits in the evening.

Amid mounting pressure, Mr Turnbull eventually resigned last Friday morning after the party voted 45-40 to hold a leadership ballot. He used his parting press conference to attack the “vengeance” and “deliberate destructive action” of his Liberal party enemies and their backers in the media.

In the party‘s leadership ballot, Mr Morrison defeated Peter Dutton, a former minister who led the rebellion.

Mr Morrison received a congratulatory tweet from Donald Trump, who fell out with Mr Turnbull over a proposed refugee swap between the countries: “Congratulations to new Australian Prime Minister Scott Morrison. There are no greater friends than the United States and Australia!”

Mr Morrison yesterday began the delicate task of forming a new cabinet. The task of restoring unity to the party will also be difficult. The ruling Liberal-National Coalition trails Labor in surveys and is widely expected to lose the next election, due by May.

Yet, at his first press conference as leader, he was unable to answer the question the nation, and the world, wants to know: why did his party remove another elected leader?