Sarah Ferguson has said she made a "gigantic error of judgement" in allowing convicted sex offender Jeffrey Eppstein to pay off some of her debts.
The Duchess accepted the US financier's offer of a £15,000 payment to a former aide to whom she owed money.
She said it had been a "terrible, terrible mistake", and denied that Prince Andrew had negotiated the deal.
She added: "I am just so contrite I cannot say. Whenever I can I will repay the money."
Prime Minister David Cameron and foreign secretary William Hague have both voiced their support for Prince Andrew as UK trade envoy following revelations about his friendship with Mr Eppstein.
But business secretary Vince Cable has taken a different view, saying that "conversations" would take place with Buckingham Palace, and it would be for the Duke to decide whether he should resign.
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