The British Labour peer, Baroness Castle of Blackburn, has claimed that Dr Mo Mowlam "was being humiliated" before her announcement that she is to quit as an MP at the next general election.
Lady Castle said the former Northern Ireland Secretary's decision to call a halt to her Parliamentary career was "a very sad day" for the Labour party.
According to the report in today's London Independent: she said "I'm very pro-Mo. If it hadn't been for Mo, there wouldn't have been a Good Friday Agreement. Then, unfortunately, Tony Blair stepped in and started making deals with the unionists and she was edged out.
"I think she was being humiliated. The Cabinet Office is a non-job. No self-respecting woman would stay in a non-job.
"She's her own woman and isn't going to pretend she's something she isn't. I think Mo's a successful politician in her own right and more successful than most men. It is a very sad day for the party."
Lady Castle added that she thought the higher reaches of government were too male dominated.
"I think Downing Street is certainly very masculine dominated. I do think that women's representation in government will suffer from Mo's departure and the Cabinet will be the weaker for it."
Earlier, Dr Mowlam rejected reports she had decided to stand down at the next election because she was "unhappy" and "hounded out", saying she simply wanted to try her hand at something else.
She also said she was still firmly behind the Labour party.
"I've hit 50 and I wanted to see if I could focus on one of the things that I've enjoyed doing in politics," she told BBC radio.
The British print media yesterday carried stories of how Dr Mowlam was either driven out of government by hostile fellow ministers or had quit because she felt she had been sidelined.
But Dr Mowlam dismissed the reports, saying she had discussed the move with Prime Minister Tony Blair "for some months".
"It is not a decision I've been forced into. It's not because of my health, it's not because of the things people have said over the years," she said.
A leading left-wing Labour MP, Ms Dianne Abbott, branded Mr Tony Blair's cabinet a "boys' own" club, uncomfortable with women like Dr Mowlam.
The MP for Hackney North and Stoke Newington, told BBC Radio 4's Today programme: ". . . I think that contrary to appearances, the Blairite inner circle is very much a kind of boys' own project and not particularly comfortable with women, particularly a woman like Mo, who, although she was absolutely loyal, was very much her own woman."