Deputy Prime Minister John Prescott "exploited power for his own sexual gratification", the diary secretary he had an affair with has said.
Tracey Temple appeared tearful in a video statement
Tracey Temple was speaking in an interview with the Mail on Sunday newspaper for which she was paid in excess of £100,000.
Ms Temple said she had gone public to "tell my side of the story".
Mr Prescott, MP for Hull East, has said he regretted the affair and it had left his wife Pauline "devastated".
Ms Temple told the newspaper she felt she had been abandoned by him when news of the affair came out. She said she had received just one phone call from her ex-lover.
"I feel I have been used and am being used as a scapegoat. They have abandoned me and hung me out to dry. I have been left completely alone," he said.
She told the newspaper "we made love in John's office" and that "we were very lucky we never got caught".
She also claims she and Mr Prescott had sex after he took her to an Iraq war memorial service.
Ms Temple alleges they had sex in a hotel while Mr Prescott's wife waited downstairs.
She said regular sexual encounters took place in his office with the door open while other civil servants worked outside.
The deputy prime minister would often interrupt official business to engage in sexual banter, she alleged.
In a video statement released on Saturday night, Ms Temple appeared tearful.
"I was not responsible for this story," she said.
"I've had to live with the lies and the misinformation that was actually written about me, causing damage to my reputation and possibly my future career.
"Therefore, as a result, I felt I needed to tell my side of the story and let people know the truth.
"But I never, ever thought that I would have had to do anything like this."
One of Mr Prescott's friends, Sports Minister Richard Caborn, told BBC News the deputy prime minister was "very depressed" over his "huge mistake" and that wife Pauline was "greatly saddened".
Colin Brown, Prescott's biographer, said he believed Mr Prescott would ride out the storm, dismissing the revelations as "sexual tittle tattle".
"It's embarrassing, but I think that's all," he said. "I don't think these allegations will prove to be the silver bullet.
"The whole thing is unexpectedly low grade."
He believed Mr Prescott's wife Pauline had decided to forgive him, which was "crucial".
And Prime Minister Tony Blair has refused to discuss the affair saying it was "a private matter".
"It would be a very bold political leader who says there will never be any problems in the personal lives of any of my ministers," he said in an interview with the News of the World.
But Daily Telegraph political editor George Jones said Mr Prescott may "decide to walk away" out of embarrassment.
"He is a very proud man and got a good record in government, but he might decide that he doesn't want to carry on when he's got all this prurient detail now being openly discussed in the newspapers."
Speaking to BBC Radio Four's Today programme on Saturday morning, Ms Temple's publicist Max Clifford said Ms Temple wanted to set the record straight and would get "an awful lot more" than the reported £100,000 fee.
He said: "She had absolutely nothing to do with the story coming out, so then she went to the Cabinet Office and her colleagues for help and advice on how to handle the media and got nothing, nothing at all.
"All they were interested in was looking after John Prescott. Meanwhile, day after day, she is reading stuff in the papers a lot of which is totally untrue."
A government spokesman said: "The Cabinet Office and the Office of the Deputy Prime Minister have been in frequent and regular contact with Tracey, providing her with support as a responsible employer."
The deputy prime minister admitted earlier this week to having an affair with Ms Temple, which immediately sparked speculation about his future in the cabinet.