McCartney versus McCartney has begun

McCartney and Mills married in 2002. Picture / Reuters

LONDON - The wedding ring is off. The dazzling team of lawyers is in place.

Sir Paul McCartney has filed for divorce, it emerged yesterday, and the publicly genial former Beatle seems to be preparing for a long, tough battle with his estranged wife, Heather.

Both had hoped for an amicable split, for the sake of their two-year-old daughter, Beatrice.

But yesterday a friend revealed that Sir Paul's petition for divorce had been submitted to the courts and it blamed the break-up of the four-year marriage on Lady Heather's "unreasonable behaviour".

The singer was said to have described his wife as "argumentative" and "rude to staff".

Lady Heather hit back by saying she would be filing counterclaims in British and American courts, putting her own side of the story.

A court battle on both sides of the Atlantic could take more than a year.

The former model turned charity campaigner might emerge with a £200m ($602m) settlement - but her lawyers will have to beat one of the most impressive legal teams ever to contest a British divorce.

It includes Fiona Shackleton, the tough divorce specialist who helped Prince Charles part from Diana, and Nicholas Mostyn QC, whose results in high-profile divorce cases have earned him the nickname Mr Payout.

Leading them from behind the scenes will be John L Eastman, long-time lawyer, manager and friend of Sir Paul - and the brother of his late wife Linda.

Sir Paul, 64, waved cheerily to photographers at his Liverpool Institute of Performing Arts on Friday, but they noticed that his ring finger was bare for the first time in four years.

"Paul just wants to get this over as quickly and cleanly as possible and put the whole sorry episode behind him," his friend was quoted as saying in the Daily Mirror yesterday, while giving details of the divorce petition.

But in The Sun "a source close to the family" said the singer was furious.

"He was determined these details would remain private, and he's very disappointed that someone in a position of trust has revealed all."

Meanwhile a statement released by Lady Heather, 38, said she was "hugely disappointed that matters of such a confidential nature should be aired in public and feels it inappropriate to speak about such delicate matters when a child is involved."

Lawyers for both sides will try to agree a compromise in private - but if they cannot do so then the secrets of the brief McCartney marriage may well be aired in a public court room, including the hostility apparently felt towards Lady Heather by her stepchildren.

This became more public earlier this month with the news that someone had bugged the line at Sir Paul's home in East Sussex, recording a conversation in which his daughter, the 33-year-old fashion designer Stella McCartney, gave full vent to her feelings, claiming, among other things, that her stepmother had lied about her past.

Sir Paul is worth an estimated £825m, thanks to his career with the Beatles and as a solo performer, plus his property and publishing companies.

His marriage to Linda Eastman lasted from 1969 to her death from breast cancer in 1998. They had three children, and he adopted her daughter by a previous marriage.

A year after Linda's death, Sir Paul went to a charity function and met Heather Mills, a 31-year-old model famous for going on working after losing part of her leg when she was hit by a police motorcycle.

The couple were married in 2002, at the remote Castle Leslie in County Monaghan. There was no pre-nuptial agreement.

- INDEPENDENT