Harriet Harman has appeared before MPs to defend her vulnerable position as leader of the House of Commons and deputy leader of the Labour party.
Ms Harman said she and her campaign team acted in good faith by accepting a £5,000 donation from Janet Kidd to help clear her debts after this summer's deputy leadership campaign.
It has since been revealed Ms Kidd was acting as a conduit for the millionaire property developer David Abrahams, who sought to donate anonymously to the Labour party "to avoid publicity".
Ms Harman has since been widely tipped to be the first casualty of Gordon Brown's government after it emerged Mr Brown and fellow deputy contender Hilary Benn rejected funds from Mr Abrahams' intermediaries.
Facing MPs today, Ms Harman said he her team had acted within the spirit and the letter of the law and had followed a number of conditions when accepting money from donors.
Because Ms Kidd was a pre-existing Labour donor, Ms Harman's campaign team willingly accepted the £5,000, she attempted to explain.
Ms Harman was blocked from offering a full statement to the House by speaker Michael Martin, who rebuked both Ms Harman and shadow Theresa May for lapsing into party politics.
Amid repeated warnings from the speaker, Ms May criticised Ms Harman for not offering a full emergency statement before the House.
Ms May insisted the Labour party's explanation for the proxy donor scandal "won't wash".
"The public know sleaze when they see it and the public know spin when they see it," she told MPs, before predicting Labour would lose the next election.
Ms Harman retorted: "The honourable lady can huff and puff but she will not blow this leader of the house down."
The government has promised to amend party funding laws pending an inquiry into the use of third-party donors.
Ministers have been keen to shift some of the blame on to the Conservatives, arguing the Tories are resisting consensus on party funding reform.