Michael Wolff, author of Fire And Fury: Inside The Trump White House, called the US President a man “who is stepping into history as the greatest liar that there has ever been”.
Speaking from New York, Mr Wolff said: “This is a president beyond reason, beyond control, beyond expectations.
“It is a president and a presidency that clearly, in every possible way, on every possible reasonable terms, doesn’t work.”
On the cancellation of Mr Trump’s visit to the UK, the author said: “I think the deeper reason is that he felt he would come to the United Kingdom and he would not receive the love he believes he deserves.
“I think he was probably supported in this decision by the people around him because they know bad things happen when this president does not receive the love he believes he deserves.”
He added: “When he feels people are not according him proper respect, proper love, proper regard for him as a legitimate president, he goes crazy.”
The President had been expected travel to London to open the new US embassy as early as next month.
However, he said on Twitter he would no longer open the embassy because he is “not a big fan of the Obama Administration having sold perhaps the best located and finest embassy in London for ‘peanuts'”.
Mr Trump has already criticised the book, calling it inaccurate and saying Mr Wolff is a “loser” who had little access and mostly relied on Steve Bannon, his former top aide and chief strategist.
The US President wrote on Twitter: “Michael Wolff is a total loser who made up stories in order to sell this really boring and untruthful book.
“He used Sloppy Steve Bannon, who cried when he got fired and begged for his job. Now Sloppy Steve has been dumped like a dog by almost everyone. Too bad!”
Mr Wolff told Sky News he thinks Steve Bannon’s contributions to the book were his way of breaking away from the President.
“My book, I suspect, was part of his plan to break with Donald Trump – who frankly, he considers an idiot.”
Asked about Mr Trump’s recent controversial comments about African countries, Mr Wolff said the President “makes these kinds of comments all the time”.
“There’s nothing new here,” he said, “this is part and parcel of what Donald Trump is… his biases and prejudices and thought patterns.”
He said it is “Trump being Trump in every way – uncontrolled, uncaring, looking to please the base without regard for what it does to everyone else. Wanting to be at the centre of attention.”
Despite Mr Trump’s claim that Mr Wolff “made up stories”, the author insists the only inaccuracies are typographical.
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“Anyone who has ever written a book always regrets typographical errors and they will surely be fixed in future editions of this book, of which apparently there will be many.”
He says his book “could not be truer” and that is why it is “so alarming”.