A former Trump administration official who penned a scathing anti-Trump op-ed and book under the pen name “Anonymous” made his identity public on Wednesday.

Miles Taylor, a former chief of staff at the Department of Homeland Security, said in a tweet: “Donald Trump is a man without character. It’s why I wrote ‘A Warning’ … and it’s why me & my colleagues have spoken out against him (in our own names) for months. It’s time for everyone to step out of the shadows.”

Speaking at a rally in Goodyear, Arizona, soon after Mr Taylor acknowledged he was the writer, Mr Trump dismissed the former administration official as “a nobody, a disgruntled employee”.

Mr Taylor has been an outspoken critic of Mr Trump’s in recent months and had repeatedly denied he was the author of the column — even to colleagues at CNN, where he has a contributor contract.

He left the Trump administration in June 2019 and endorsed Democrat Joe Biden for president this summer.

In a statement, White House press secretary Kayleigh McEnany called Mr Taylor a “low-level, disgruntled former staffer” who “is a liar and a coward who chose anonymity over action and leaking over leading”.

“This is everything people hate about Washington — two-faced liars who push their own agendas at the expense of the People,” she later tweeted. “This is the epitome of the swamp!”

White House chief of staff Mark Meadows called Mr Taylor’s revelation “a monumental embarrassment,” tweeting, “I’ve seen more exciting reveals in Scooby-Doo episodes.”

Mr Taylor’s anonymous essay was published in 2018 by The New York Times, infuriating the president and setting off a frantic White House leak investigation to try to unmask the author.

In the essay, the person, who identified themselves only as a senior administration official, said they were part of a secret “resistance” force out to counter Mr Trump’s “misguided impulses” and undermine parts of his agenda.

The author wrote, “Many Trump appointees have vowed to do what we can to preserve our democratic institutions while thwarting Mr Trump’s more misguided impulses until he is out of office.”

The newspaper, which said it had granted Mr Taylor anonymity because his job would be jeopardised if his identity was revealed, on Wednesday confirmed Mr Taylor was the author because he has waived his right to confidentiality, and had no other comment.

The allegations incensed the president, bolstering his allegations about a “deep state” operating within his government and conspiring against him.

And it set off a guessing game that seeped into the White House, with current and former staffers trading calls and texts, trying to figure out who could have written the piece.

Trump Anonymous
Former Department of Homeland Security chief of staff Miles Taylor, right, made his identity public on Wednesday (Tim Godbee/Department of Homeland Security via AP)

Mr Trump, who had long complained about leaks in the White House, also ordered aides to unmask the writer, citing “national security” concerns to justify a possible Justice Department investigation.

And he issued an extraordinary demand that the newspaper reveal the author.

Instead, the author pressed forward, penning a follow-up book published last November called “A Warning” that continued to paint a disturbing picture of the president, describing him as volatile, incompetent and unfit to be commander in chief.

In an essay published on Wednesday on Medium.com, Mr Taylor said he published the op-ed and book anonymously because he wanted the focus to be on the arguments, instead of who was writing them.

“We got the answer,” he wrote. “He became unhinged. And the ideas stood on their own two feet.”

Mr Taylor said the nation could no longer rely on bureaucrats to steer Mr Trump toward what is right since “he has purged most of them anyway”.

“He doesn’t deserve a second term in office,” he wrote, “and we don’t deserve to live through it.”