Paul and Heather Mills McCartney have raised the stakes in their increasingly acrimonious divorce battle, hiring the same two lawyers who represented Prince Charles and Princess Diana when they split in 1996.

Mills, who married the former Beatle in 2002 and had a daughter, Beatrice, with him, has named Anthony Julius of leading law firm Mishcon de Reya to fight her side. Julius represented Diana in the divorce case.

"Yes. It was decided today," said Mills' spokesman Phil Hall on Tuesday, when asked to confirm Julius' appointment.

It has already been widely reported that McCartney had hired Fiona Shackleton, who acted for Prince Charles against Diana, to argue his case.

Prince Charles married Lady Diana Spencer in 1981, but the marriage collapsed amid mutual accusations of adultery. They separated in 1992 and finally divorced in 1996.

When the McCartneys announced their separation in May, they promised it would be amicable.

But Hall confirmed on Tuesday that McCartney had frozen their joint bank account and sent a "legal letter" to his wife recently to complain after three bottles of cleaning fluid were taken from his Sussex home to clean Mills' nearby office.

McCartney's spokesman was not available for comment.

"UNREASONABLE BEHAVIOR"

McCartney, 64, cited Mills' "unreasonable behavior" in divorce papers, and Mills, who is 38, responded by vowing to file counterclaims in Britain and the United States.

"She is hugely disappointed that matters of such a confidential nature should be aired in public and feels it is inappropriate to speak about such delicate matters when a child is involved," her spokesman said in a statement last month.

Lawyers believe McCartney could lose up to one quarter of his wealth, estimated at 825 million pounds ($1.5 billion), as a result of a divorce, partly because he did not sign a prenuptial agreement.

The couple met in 1999 at a charity event a year after the death from breast cancer of McCartney's first wife Linda.

Mills has been the target of lurid allegations in British tabloids since separating from McCartney, but he has strongly denied she married him for his money, saying in May there was "not an ounce of truth in this."

Earlier on Tuesday, Hall said Mills had laughed off being locked out of McCartney's London home.

On Monday, police were called to the residence when Mills' security guard climbed over the wall of his premises to let her in. The locks on the gates had been changed.

"One of the security people inside called the police," Hall said. "They turned up and she went off for a drive around the block with the kid."

Mills had arrived at the home with daughter Beatrice.

"She was laughing about it," Hall said, when asked about newspaper reports that Mills was angry at being locked out.