A day before the deadly attack on the US Capitol, Mike Pence’s chief of staff warned the head of Pence’s Secret Service detail that Donald Trump was about to turn on his own vice-president, endangering his security.

The news was reported on Friday by Maggie Haberman of the New York Times, who said she uncovered it during research for a book on Trump due out in October.

On 5 January, Haberman wrote, Pence’s chief of staff, Marc Short, did not know how his boss’s security might be threatened if Trump turned on him. But Trump and advisers had been formulating a plan under which Pence would stop certification of electoral college results in Trump’s defeat by Joe Biden.

Under pressure which the Times said included withholding funding for the vice-president’s transition out of power, Pence considered the plan before concluding he did not have the authority to reject electoral college results.

When the mob attacked the Capitol on 6 January, rioters were heard to chant “Hang Mike Pence” while a gallows was set up outside.

The Times recently reported that two witnesses who spoke to the January 6 committee said Trump told Mark Meadows, his own chief of staff, “something to the effect of, maybe Mr Pence should be hung”.

The Times said it was not clear if Trump was serious.

Trump told another reporter and author, Jon Karl, his supporters “were very angry” with Pence and that it was just “common sense” to be so, because Pence was not helping overturn Trump’s election defeat.

The Times said it was not clear what Tim Giebels, the head of Pence’s Secret Service detail, did with the warning from Short.

The next day, with the Capitol under attack, Pence’s protectors rushed him from the Senate chamber to an underground parking bay. Multiple accounts have said the vice-president refused to leave the building.

According to Short, Pence said: “I’m not going to let the free world see us fleeing the Capitol, and I’m staying.”

Authors of books on the Trump presidency have been widely criticised for withholding news until publication. Haberman was known for having strong sources in the Trump White House, and was filmed taking calls from Trump himself.

She published her nugget about Trump’s threat to Pence in the run-up to public hearings due to be staged by the House committee investigating the events of 6 January 2021.

Pence and the Secret Service did not comment on the new Times report.