Edwina Currie has accused her former lover John Major of behaving "atrociously".
She also described his 'Back to Basics' campaign as "evil".
Mrs Currie defended her decision to expose their affair 14 years after it ended.
The former British Tory minister insisted she had called off the four-year relationship when he got a job in Margaret Thatcher's Cabinet.
She said neither of them had "stopped caring for each other" but the risks were too great.
Mrs Currie said: "I ended it by writing to John. I didn't want to but it seemed to me that now he was in the Cabinet we were running far too many risks."
And she made clear her anger at his comment last weekend he was "ashamed" of their liaison.
"He may say now that he was ashamed of it, but he wasn't ashamed of it then and he wanted it to go on," she told the BBC in her first broadcast interview about the affair.
Mrs Currie spoke of the "burden" of her affair with Mr Major as she told of her need to "set the picture straight" by publishing her diaries.
She said she believed that most of the main actors in her diaries were now consigned to political "oblivion" and their careers would not be harmed.
She admitted her two daughters were "a little surprised" by the revelations of the four year affair.