- Video report by ITV News Washington Correspondent Robert Moore
US President Donald Trump says he no longer speaks to Steve Bannon as the former White House chief strategist was threatened with legal action by the president's lawyer over an explosive new book.
Mr Trump told reporters "I don't talk to him" when questioned about Mr Bannon's comments in Michael Wolff's new book Fire and Fury: Inside the Trump White House.
In the book, Mr Bannon is quoted as describing a June 2016 meeting at Trump Tower between Donald Trump Jr, Trump campaign aides and a Russian lawyer as "treasonous" and "unpatriotic", and also questions his fitness for office.
Mr Bannon also speaks critically of president Trump's daughter and adviser, Ivanka, calling her "dumb as a brick".
Mr Trump was said to be "furious" and "disgusted" by Mr Bannon's comments which surfaced when excerpts of the book were published in New York magazine, The Hollywood Reporter and GQ.
In a statement on Thursday, Mr Trump said his former strategist "has nothing to do with me or my Presidency", adding: "When he was fired, he not only lost his job, he lost his mind".
Fire and Fury paints an unflattering picture of Mr Trump, with Mr Wolff portraying him as a leader who does not understand the weight of the presidency and spends his evenings eating cheeseburgers in bed, watching television and talking on the phone to old friends.
Following the release of excerpts of the book - which is listed for publication on January 9 - Mr Wolff tweeted to say that the book would be available from Friday.
On Wednesday, Mr Trump's lawyer, Charles Harder, threatened legal action against the former aide over "disparaging statements and in some cases outright defamatory statements".
Mr Harder wrote to Mr Bannon, saying he had violated confidentiality agreements by speaking to Mr Wolff.
His letter demanded Mr Bannon "cease and desist" any further disclosure of confidential information.
Speaking on Thursday at the White House, Mr Trump said Bannon spoke positively of him Wednesday night on his Breitbart radio show.
"He called me a great man last night," Mr Trump noted, adding that his counter-attack had its desired outcome.
"He obviously changed his tune pretty quick."
An attorney for Mr Trump has threatened Mr Bannon with legal action, accusing him of violating written confidentiality and non-disparagement agreements.
Lawyer Charles J. Harder said Bannon's actions "give rise to numerous legal claims including defamation by libel and slander". In a letter, he advised Mr Bannon to stop discussing Mr Trump or his family with any journalists, authors or bloggers.
Former White House national security aide Sebastian Gorka told ITV News the book was a "non-event" and "silly distraction".
- Watch Robert Moore's full interview with Sebastian Gorka
Mr Gorka, who himself left the White House last August in unexplained circumstances, said the book would be forgotten a week from now because of everything Mr Trump had achieved since the start of his four-year term.
"Michael Wolff is a hack," Mr Gorka said.
"This is palace intrigue, it's fluff."
Blair denies he warned Trump of UK spying
The book also features allegations that Tony Blair warned Mr Trump that UK intelligence agencies may have spied on him, something the former prime minister said is "a complete fabrication".
The book claims Mr Blair shared a "juicy rumour" with the president's son-in-law and senior aide Jared Kushner that the British had Trump campaign staff under surveillance during the election.
It is claimed Mr Blair suggested they were "monitoring telephone calls and other communications and possibly even Trump himself".
The "categorically absurd" allegations, published in The Times, have "no basis in reality and are simply untrue", according to Mr Blair's spokeswoman.
Mr Blair told ITV News: "This story is literally a fabrication from beginning to end. I've never had any such conversation, not merely with someone in the White House, but with anyone, anywhere at any point in time.
"Anybody who knows the British intelligence services...the idea that they would start interfering in an American presidential campaign is literally absurd."
The Times reported that Mr Wolff's book contains an account of a meeting between Mr Blair and Mr Kushner at the White House last February.
The former PM reportedly gave the impression that Barack Obama's administration had hinted that surveillance of Trump campaign staff during the election would be helpful.
A month after the supposed meeting, former White House press secretary Sean Spicer provoked a trans-Atlantic spat by repeating claims made on Fox News that Mr Obama had asked British intelligence to spy on Trump Tower.
British spy agency GCHQ dismissed the claims at the time as "utterly ridiculous".
Excerpts of Fire and Fury have been published ahead of the January 9 publication date.
New York magazine published a lengthy adaptation of the book on Wednesday, in which Mr Wolff writes that Mr Trump believed his presidential nomination would boost his brand and deliver "untold opportunities" - but that he never expected to win.
It also claims Mr Trump Jr told a friend that his father looked as if he had seen a ghost when it became clear he might win the presidency. The younger Trump reportedly described First Lady Melania Trump as "in tears - and not of joy" when it became clear he would win.
The first lady's spokeswoman, Stephanie Grisham, disputed that, saying Mrs Trump supported her husband's decision to run, encouraged him to do so and was happy when he won.
"The book is clearly going to be sold in the bargain fiction section," Ms Grisham said.
White House Press Secretary Sarah Huckabee Sanders called the book a "trashy tabloid fiction expose" and said accounts inside it came from "individuals who have no access or influence with the White House".
The book was based on more than 200 interviews, including conversations with the president and senior staff.