There are few situations where hanging up on someone mid-phone call is considered acceptable, least of all an important call between two national leaders.

And yet that is reportedly what Donald Trump did just 25 minutes into what was meant to be an hour-long conversation with Australian Prime Minister Malcolm Turnbull.

According to the Washington Post, the US President abruptly ended the call with Turnbull over his demand that the US honour the refugee deal agreed with former President Barack Obama.

Donald Trump's top five Twitter feuds

Trump apparently subjected Turnbull to a torrent of vitriol (which the world has seen many a time on Twitter), became exasperated and started yelling, before terminating the conversation.

It is behaviour largely associated with stroppy teenagers who can’t deal with not getting their way, but does acting like this suggest yet another worrying red flag when it comes to the new POTUS?

Behavioural and celebrity psychologist Jo Hemmings believes Trump’s behaviour on the phone is another large indicator of his malignant narcissism.

“He has a messiah complex, no conscience, and lacks complete empathy,” she told The Independent, adding that hanging up the phone is “just like a child having a tantrum.”

According to Hemmings, most people grow out of this behaviour by the age of three or four, although there’s sometimes a reappearance during adolescence due to hormones.

The controversial orders Donald Trump has already issued Show all 9 1 /9 The controversial orders Donald Trump has already issued The controversial orders Donald Trump has already issued Trump and the media White House Press Secretary Sean Spicer takes questions during the daily press briefing Getty Images The controversial orders Donald Trump has already issued Trump and the Trans-Pacific Partnership Union leaders applaud US President Donald Trump for signing an executive order withdrawing the US from the Trans-Pacific Partnership negotiations during a meeting in the Roosevelt Room of the White House in Washington DC. Mr Trump issued a presidential memorandum in January announcing that the US would withdraw from the trade deal Getty The controversial orders Donald Trump has already issued Trump and the Mexico wall A US Border Patrol vehicle sits waiting for illegal immigrants at a fence opening near the US-Mexico border near McAllen, Texas. The number of incoming immigrants has surged ahead of the upcoming Presidential inauguration of Donald Trump, who has pledged to build a wall along the US-Mexico border. A signature campaign promise, Mr Trump outlined his intention to build a border wall on the US-Mexico border days after taking office Getty Images The controversial orders Donald Trump has already issued Trump and abortion US President Donald Trump signs an executive order as Chief of Staff Reince Priebus looks on in the Oval Office of the White House. Mr Trump reinstated a ban on American financial aide being granted to non-governmental organizations that provide abortion counseling, provide abortion referrals, or advocate for abortion access outside of the United States Getty Images The controversial orders Donald Trump has already issued Trump and the Dakota Access pipeline Opponents of the Keystone XL and Dakota Access pipelines hold a rally as they protest US President Donald Trump's executive orders advancing their construction, at Columbus Circle in New York. US President Donald Trump signed executive orders reviving the construction of two controversial oil pipelines, but said the projects would be subject to renegotiation Getty Images The controversial orders Donald Trump has already issued Trump and 'Obamacare' Nancy Pelosi who is the minority leader of the House of Representatives speaks beside House Democrats at an event to protect the Affordable Care Act in Los Angeles, California. US President Donald Trump's effort to make good on his campaign promise to repeal and replace the healthcare law failed when Republicans failed to get enough votes. Mr Trump has promised to revisit the matter Getty Images The controversial orders Donald Trump has already issued Donald Trump and 'sanctuary cities' US President Donald Trump signed an executive order in January threatening to pull funding for so-called "sanctuary cities" if they do not comply with federal immigration law AP The controversial orders Donald Trump has already issued Trump and the travel ban US President Donald Trump has attempted twice to restrict travel into the United States from several predominantly Muslim countries. The first attempt, in February, was met with swift opposition from protesters who flocked to airports around the country. That travel ban was later blocked by the Ninth Circuit Court of Appeals. The second ban was blocked by a federal judge a day before it was scheduled to be implemented in mid-March SANDY HUFFAKER/AFP/Getty Images The controversial orders Donald Trump has already issued Trump and climate change US President Donald Trump sought to dismantle several of his predecessor's actions on climate change in March. His order instructed the Environmental Protection Agency to reevaluate the Clean Power Plan, which would cap power plant emissions Shannon Stapleton/Reuters

“Trump acts like a child who hasn’t yet developed enough to consider anyone else’s opinion,” Hemmings says.

She believes that the President’s behaviour further suggests he’s never wanted for anything in his life or had to modify his behaviour, which has fueled his narcissism.

“Trump is clearly used to getting his own way and is very hot-headed,” she says. “He won’t see things from anyone else’s perspective and gets very annoyed when challenged.”

The President’s malignant narcissism results in a desperate need and entitlement for power, according to Hemmings, and she says Trump is likely to see no point in continuing a conversation after someone disagrees with him because he’s “massively bloody-minded.”

But as we have already seen, not all the world leaders will play his game and Trump will fall out with anyone who doesn’t agree with him, which is likely to lead to problems down the line.

“Trump thinks he’s invincible,” says Hemmings, who doubts whether his advisors will ever question or criticise him.

“Usually leaders choose the people around them to keep them in check, and Trump needs people to temper his hotheadedness and aggression. Instead, he’s picked advisors who worship him.”