The Duchess of York was filmed offering to sell access to ex-husband Prince Andrew for £500,000, a newspaper has claimed.

The News of the World said Sarah Ferguson promised to introduce an undercover reporter posing as a wealthy businessman to the Prince, who has been the UK's special representative for international trade and investment since 2001.

The paper claims she was filmed on Tuesday night accepting a $40,000 cash down-payment and it quotes her as saying: "I can open any door you want."

And it alleges that she asked for the main £500,000 payment to be wired to her UK bank account.

On the video soundtrack, the Duchess apparently tells the undercover reporter: "£500,000 when you can, to me, open doors".

The paper said despite the Prince knowing nothing about the deal, the Duchess claimed to have discussed it with him: "Andrew said to me, 'Tell him £500,000'.

"He knows that he's had to underwrite me up to now because I've got no money. So if you want to meet him in your business, look after me and he'll look after you ... you'll get it back tenfold."