Donald Trump’s co-author of his 1987 book The Art of the Deal says he believes the president is having a “meltdown” and that it is a “true emergency”.

In a recent interview with CNN’s Brian Stelter, author Tony Schwartz said he believed it was important to publicly call attention to Mr Trump’s behaviour, which he described as “out of the norms”. Mr Stelter had previously asked Mr Schwartz whether continuous speculation over Mr Trump was dangerous.

“We need to keep front and centre that this is a person who is far outside the norms of ordinary behaviour,” he said. He added that he believed Mr Trump’s trip to Europe further proved the US president was having a “meltdown” as a result of pressure and feeling “under siege”.

Mr Trump notably criticised PM Theresa May in an interview with The Sun, published the same day he arrived in London, over UK’s Brexit deal. Mr Trump later denied the criticism during a press conference with Ms May, labelling the story published in the conservative Rupert Murdoch-owned paper as “fake news”.

Further, Mr Trump’s Europe trip has also been marked by his arrival at the NATO summit in which he accused Germany of being “a captive of Russia,” amid reports detailing his strong criticisms towards allies for not spending enough on defence during the summit.

When asked why he felt confident to label Mr Trump as having a “meltdown,” Mr Schwartz cited his “enormous” amount of time with the president – over a period of 18 months – and being a “25-year student of psychology” as justifications, to name a few.

Nato leaders gather for summit: in pictures Show all 10 1 /10 Nato leaders gather for summit: in pictures Nato leaders gather for summit: in pictures World leaders gather for Nato family photo Getty Images Nato leaders gather for summit: in pictures British Prime Minister Theresa May arrives EPA Nato leaders gather for summit: in pictures President Donald Trump talks to British Prime Minister Theresa May EPA Nato leaders gather for summit: in pictures U.S. President Donald Trump, left, talks to British Prime Minister Theresa May during a family photo at a summit of heads of state and government at NATO headquarters in Brussels Wednesday, July 11, 2018. NATO leaders gather in Brussels for a two-day summit to discuss Russia, Iraq and their mission in Afghanistan. (AP Photo/Markus Schreiber) Markus Schreiber AP Nato leaders gather for summit: in pictures US President Donald Trump and Nato Secretary General Jens Stoltenberg attend a bilateral breakfast ahead of the Nato Summit in Brussels Reuters Nato leaders gather for summit: in pictures President Donald Trump, right, gestures as he speaks to the media prior to his bilateral breakfast with Nato Secretary General Jens Stoltenberg, left AP Nato leaders gather for summit: in pictures President Donald Trump, US Secretary of Defence James Mattis and US Secretary of State Mike Pompeo at the bilateral breakfast with Nato Secretary General Jens Stoltenberg REUTERS Nato leaders gather for summit: in pictures President Donald Trump and Mike Pompeo, left, are reflected in a mirror as they attend at a breakfast meeting AFP/Getty Images Nato leaders gather for summit: in pictures President Donald Trump speaks during the bilateral breakfast EPA Nato leaders gather for summit: in pictures President Donald Trump gestures during the bilateral breakfast EPA

“I believe the republic is at enormous risk that goes far beyond what most journalists are comfortable saying and what the general public therefore – it doesn’t really fully understand,” he said. He added: “We are in a true emergency.”

Mr Schwartz said his tweets and on-air interviews are his attempts to warn the general public; he added that he’s trying to be “Paul Revere" - the 18th Century metalworker celebrated for warning American militias about the arrival of British troops.

Loading....

Mr Schwartz has been critical of Mr Trump throughout his presidency.

During his interview with Mr Stelter, he acknowledged he previously predicted Mr Trump would resign from office by 2017.

“You’re absolutely right, I completely missed it,” he said. “I think I got it wrong, I think I underestimated the enormous attachment that he would have to being in that office.”