The culture secretary has been one of the prime minister’s most fervent supporters, and he stuck with him even as support for his leadership collapsed in Westminster.
In a previously released clip from BBC Panorama, Ms Dorries said: “I was quite baffled that there were people who thought removing the Prime Minister who won the biggest majority we’ve had since Margaret Thatcher in less than three years.
“Just the anti-democratic nature of what they’re doing was enough to alarm me.
“And for me it was a coup.”
The full interview on the investigative TV show will air later on Wednesday.
Ms Dorries made the same claim on Monday, when she also criticized those who took action against Johnson.
“14 million people voted for the prime minister and a group of MPs, ministers, the chancellor, his incumbent chancellor, through what is basically a coup d’état have removed him,” she told GB News.
Ms Dorries has thrown her weight behind Secretary of State Liz Truss in the Tory leadership contest that will select Mr Johnson’s successor at number 10.
She led an attack on Mrs. Truss’ rival, Rishi Sunakwhose resignation as chancellor last week is seen by Johnson allies as key to ending the prime minister’s hold on number 10.
Ms Dorries accused Mr Sunak’s campaign team of using the “dark arts” after claims they were trying to “wash off” votes to ensure Jeremy Hunt passed the contest threshold, believing that Mr. Sunak would beat him in a second ballot of party members.