Colin Powell, who served in the earliest years of the George W Bush administration as US Secretary of State, has been caught calling this year’s Republican nominee, Donald Trump, a “national disgrace and an international pariah.”

The intemperate outbursts about his own party’s choice for White House candidate this year are contained in hacked private email musings. They reveal that the former army general is also not a huge of fan of Hillary Clinton, the Democratic nominee.

Last year, as Ms Clinton was already trying to stave off the scandal about her use of a private email server while she had the post of Secretary of State, he observed: “Everything HRC touches she kind of screws up with hubris”.

But it is Mr Trump who comes off the worst in passages of the hacked emails that were first published on DCLeaks.com, a website set up to help hackers publicise their findings that is said to have links to Russian intelligence groups.

Mr Powell, who is African-American, expresses his disbelief, for instance, over Mr Trump’s attempts to suggest that black voters will soon rush into his arms. “For him to say yesterday that within four years he would have 95 per cent of blacks voting for him is schizo fantasy,” he wrote.

He similarly excoriates him for his attempts several years ago to question the place of birth of President Barack Obama as being simply “racist”.

“Yup, the whole birther movement was racist,” Mr Powell wrote. “When Trump couldn't keep that up he said he also wanted to see if the certificate noted that he was a Muslim.” In that instance, he was engaging with a journalist, Emily Miller, who was once one of his aides. It was in the same email that he called Mr Trump a “pariah”.

Loading....

He added in the same exchange that Mr Trump “appeals to the worst angels of the GOP nature and poor white folks”. The surfacing of the emails was first reported by Buzzfeed News.

Mr Powell confirmed to NBC News on Wednesday that the leaked emails had indeed been written by him and suggested that because his email security had clearly been compromised there was reason to believe more of his conversations would surface.

In an email to Fareed Zakaria, a CNN anchor, late last year, Mr Powell also complained about breathless coverage of Mr Trump. “You guys are playing his game, you are his oxygen,” he laments. “He outraged us again today with his comments on Paris no-go for police districts.”

He also said that he himself had tried to avoid paying public attention to Mr Trump because it would only give him more oxygen. “To go on and call him an idiot just emboldens him,” he said.

Much of his disdain for Ms Clinton seems to stem from her mishandling of the private server affair and in particular attempts that she and her staffers made to say she was actually following an example he had set when he was Secretary of State. Mr Powell has indeed acknowledged that he did not use a government email system for some private communications.

Last month, he wrote that Ms Clinton, “could have killed this two years ago by merely telling everyone honestly what she had done and not tie me into it. I told her staff three times not to try that gambit.” In an email reported by NBC, Mr Powell wrote that he had told Ms Clinton’s ”minions repeatedly that they are making a mistake trying to drag me in, yet they still try”. In another missive he compains that “Clinton's mafia keep coming after me”.