The Duchess of York is "devastated" and "regretful" after she was filmed apparently offering to sell access to her ex-husband Prince Andrew for £500,000, sources have said.

A News of the World video showed Sarah Ferguson promising 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 Duchess is expected in Los Angeles later where she is scheduled to pick up an award for her charity work.

In the film on the newspaper's website, she is shown telling the reporter: "£500,000 when you can, to me, open doors."

Asked if she was referring to the Prince, she said "Yeah", then shook hands with the reporter before apparently accepting a 40,000 US dollar (£27,600) cash down-payment.

She was filmed apparently telling him how to transfer £500,000 to her bank account, saying: "Then that, is then like, then you open up all the channels whatever you need, whatever you want, and then that's what and then you meet Andrew and that's fine. And that's, that's when you really open up whatever you want."

The Duchess was filmed explaining how the Prince meets the "the most amazing people" in his role as special representative, but insisted he "is completely whiter than white".

In one scene from the film, the Duchess is shown sitting in front of a table with a large amount of cash laid out on it.

The paper said despite the Prince knowing nothing about the deal, the Duchess claimed to have discussed it with him, saying: "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."

A Buckingham Palace spokeswoman said they would not comment on the allegations.