Hillary Clinton launched a “f***-laced” rant about Donald Trump, calling him “disgusting”, it has been reported.

The foul-mouthed “fusillade” came as the then-Democratic nominee for US president prepared for a debate against the tycoon in 2016.

It is recounted in a new book by New York Times journalist Amy Chozick, who said Ms Clinton was concerned at the time that voters did not perceive her as authentic, and was also intent on keeping her personal dislike of Mr Trump out of her public appearances.

“Aides understood that in order to keep it all together on stage, Hillary sometimes needed to unleash on them in private,” Ms Chozick wrote in Chasing Hillary: Ten Years, Two Presidential Campaigns and One Intact Glass Ceiling.

The two private feelings merged into one rant in front of her campaign team, Ms Chozick wrote in an excerpt quoted by The Guardian.

According to Ms Chozick: “‘You want authentic, here it is!’ she’d yelled in one prep session, followed by a f***-laced fusillade about what a ‘disgusting’ human being Trump was and how he didn’t deserve to even be in the arena.”

Ms Clinton has already released her own campaign memoir, titled What Happened.

In it, she described her revulsion at sharing a stage with Mr Trump following the leak of the Access Hollywood tapes and his infamous “grab ‘em by the p***y” comments.

Hillary Clinton's life in pictures Show all 10 1 /10 Hillary Clinton's life in pictures Hillary Clinton's life in pictures Hillary Rodham Clinton as a Wellesley College senior Getty Hillary Clinton's life in pictures Bill Clinton and Hillary Rodham in at Wellesley College Getty Hillary Clinton's life in pictures Hillary Rodham Working with the House Committee on Nixon's Impeachment Case Getty Hillary Clinton's life in pictures US Presidential candidate Bill Clinton with wife Hillary and daughter Chelsea at the Democratic National Convention Getty Hillary Clinton's life in pictures Bill and Hillary Clinton at the Inaugural Ball Getty Hillary Clinton's life in pictures Bill and Hillary Clinton with Barbara Bush Getty Hillary Clinton's life in pictures First Lady Hillary Rodham Clinton, President William Jefferson Clinton their daughter Chelsea, at the first state dinner of the Clintons administration Getty Hillary Clinton's life in pictures Hillary Clinton meets with 12 chidren in response to their letter to the President concerning their health problems Getty Hillary Clinton's life in pictures Nelson Mandela jokes with First Lady Hillary Clinton Getty Hillary Clinton's life in pictures Senator Hillary Rodham comforts Maren Sarkarat the conclusion of the Family Memorial Service held at Ground Zero of the WTC Getty

“It was the second presidential debate and Donald Trump was looming behind me,” Ms Clinton wrote. “Two days before, the world heard him brag about groping women. Now we were on a small stage and no matter where I walked, he followed me closely, staring at me, making faces.”