By Gabriel Huntley
Harriet Harman has sparked controversy by criticising "all-male leadership", which she described as "a thoroughly bad thing".
The deputy leader of the Labour party, who is taking on the prime minister's duties while he is on holiday, made the comments on the BBC's Andrew Marr show and in a Sunday Times interview headlined 'Look out, boys - I'm in charge now'.
She also announced that she is seeking to change party rules to ensure that one of its top jobs is always filled by a woman.
Harman's comments have been read as an implicit criticism of Gordon Brown, and she has been accused of re-opening the debate about his leadership.
Former deputy prime minister John Prescott criticised Harman for the comments, accusing her of promoting her own bid to succeed Gordon Brown.
On his blog, he responded: "Quotes like this just raise leadership issues once again just at a time when we should all be pulling together and defending our record."
"Success doesn't come from saying all-male leaderships are bad. You can't dictate equality in leadership elections. You must let the party decide."
In June, accusations of sexism clouded the debate about Brown's leadership which followed Labour's disastrous showing in the local elections.
Caroline Flint attacked Gordon Brown's treatment of female cabinet members as "window dressing", citing this as the reason for her resignation. Patricia Hewitt, another former minister, accused Brown's male inner circle of being "rather laddish in its culture".
At the end of this week, Lord Mandelson will temporarily take over the prime minister's duties, amid rumours he is considering resigning as a peer and re-entering the House Of Commons in order to boost his chances of succeeding Mr Brown as Labour leader.
Allies of the business secretary played down the rumours over the weekend.