A Labour peer has challenged the Commons authorities to take her to court over a demand for repayment of expenses claimed when she was an MP.
Baroness Adams - who was MP for Paisley North until 2005 - was told in February to repay £4,110 in disputed mortgage payments after a review by Sir Thomas Legg.
She is among six former Labour MPs who are yet to meet his repayment demands according to figures released by officials on Thursday - and one of four who insist they do not owe any money.
Sir Thomas ordered hundreds of politicians to hand back a total of £1.3 million following a review of claims from 2004-8 commissioned at the height of the Westminster pay and perks scandal.
As at the beginning of last month however, nearly £50,000 of that was still outstanding, a reply to a freedom of information request by BBC Radio 4's The World at One showed. It said two of the ex-MPs, Helen Clark and John Lyons, had now agreed to return the sums required by the review - £2.808 and £10,894 respectively.
Three other cases - all involving claims for mortgage interest - were listed as "under dispute": Lady Adams, former defence minister Ivor Caplin (£17,865) and Diana Organ (£12,803).
Lady Adams complained that the inquiry team was unwilling to accept the evidence she had to show her claim was a valid one - and vowed to fight the demand. "They said they were no longer interested and they were not prepared to go over Sir Thomas' report again and couldn't accept the evidence," she told The World at One.
"I wrote back to them again saying 'you seem to be more interested in upholding the report than finding the truth and for that reason I will not be paying back what I don't owe. If they want to take me to court I will be quite happy to go."
Legal action is being considered as an option by the authorities, a spokeswoman said.
The sixth former MP involved, Lorna Fitzsimons, who was told to repay £500 of the cost of a £2,700 suite because it "exceeded the guideline price", said: "Mine is a point of principle. I will settle any bill that anybody says I owe on receipt of evidence that the rule existed and I broke it."
