The reputation of Princess Diana's former butler Paul Burrell has sunk to a new low after reports he boasted of sleeping with her.

Mr Burrell apparently made the shock confession to his wife's brother, Ron Cosgrove.

Mr Cosgrove, 61, told Britain's News of the World: "In 1993, while Paul was working for the princess at Kensington Palace, he suddenly told me he'd been having a sexual relationship with her."

Mr Burrell went into detail about the affair and even claimed he was on call as the princess's lover.

"Paul told me that he'd get a call from Diana in the middle of the night specifically to have sex with her," Mr Cosgrove said.

"I told him if it was true, I was disgusted because he was married to my sister and cheating on her.

"He didn't see that as a problem. He just replied, 'Yes, but it is the princess'. He boasted they were in love."

Mr Burrell is despised in the UK for shamelessly cashing in on his association with the princess, building up an estimated 25 million pound fortune.