Left-wing Labour MP Diane Abbott has announced she is in the running for the party leadership, becoming the first woman to enter the race.
In a surprise move, Ms Abbott said she was confident of attracting the 33 nominations needed to get her on to the ballot paper.
She becomes the sixth participant in the contest, after David Miliband, Ed Miliband, Ed Balls, John McDonnell and Andy Burnham.
There had been concern in the party at the lack of a female challenger to take over from Gordon Brown as Labour leader, with Harriet Harman and Yvette Cooper both saying they would not stand.
Speaking earlier on radio, Ms Abbott said: "We need to speak to our supporters and speak to our members in a way that we are not speaking to them up until now."
Of her prospects, she added: "We think that we can get the 33, because I am attracting support not just from the Left but from women and other MPs that want to see a more diverse range of candidates."