Macca £825m divorce war

Ms Mills, 39, appeared close to a record £50 million share of her estranged husband's £825 million fortune. They parted in May last year after four years of marriage.

To ensure secrecy in Court 16 on the sixth floor of the Royal Courts of Justice in Holborn, the spyhole on the door was covered from the inside. A barricade of office chairs prevented access and the hearing was listed discreetly by just its case number. Ms Mills arrived first for the private hearing in which the two sides will try to agree a settlement with a judge present to offer guidance.

Ms Mills was driven in via a back entrance in a black Mondeo accompanied by a minder and a companion, believed to be her sister Fiona.

The car's rear window was obscured with a mat while a blanket was held up to shield her. Ms Mills, holding on to crutches, was helped from the car and into a wheelchair before being pushed inside.

Sir Paul, 65, arrived half an hour later, having stopped off for a cup of tea at a café close to his home in St John's Wood. He was driven to the same back entrance in a Lexus at about 10am. Wearing a dark blue suit, the former Beatle acknowledged journalists but said nothing.

The pair were later taken up to Court 16 using the judge's back staircase, avoiding all public spaces. The discussions between the couple and their expensively assembled legal

team are expected to last all day. Ms Mills's lawyer Anthony Julius, who also acted for Princess Diana, was at her side.

The morning session lasted two hours. A lawyer went to buy lunch for those inside. As she left she turned to confirm the order saying: "Two vegetarians and a diet Coke?" About 15 minutes later she returned carrying three bags from Pret a Manger containing sandwiches, mineral water and soft drinks.

Sir Paul made a brief appearance outside the courtroom as the session broke for lunch. He emerged eating a slice of cake. As he walked back in he smiled at reporters and asked: "Are you having fun?" He then opened the door to the courtroom and pretended to stagger in as if he were about to collapse. A woman who mistakenly wandered into the court while the door was unlocked was quickly ushered out.

The hearing, called a financial dispute resolution (FDR), is designed to sort out a settlement without the couple going to a full-blown divorce case. McCartney will be anxious to avoid publicity with Ms Mills. In leaked divorce papers, she accused him of assaulting her on four occasions, a claim he vehemently denies.

For today's hearing all court listings had been taken down but it is thought the hearing was taking place in front of Mr Justice Coleridge. The judge will hear all evidence on the case and all offers and demands in a divorce battle that has so far run for well over a year. He will then indicate what a court would order - within a range of figures - with expectation on Sir Paul and Ms Mills to reach agreement.

Reports today claim Sir Paul may offer his estranged wife a lump sum of £15million with an additional £3 million a year until their daughter Beatrice, who is nearly four, reaches her 18th birthday. That would dwarf the current record of £48 million awarded to Beverley Charman in her divorce from insurance broker John Charman in May. Mr Justice Coleridge presided over that case.

Ms Mills's spokesman Phil Hall said his client needed a wheelchair because of recent problems with her prosthetic limb. He said: "Heather has been having problems with her leg lately. It's been swelling up and she's had difficulties getting her prosthetic on. But it could also be because the last time she faced the press on crutches, she was knocked over."

He said reports Ms Mills could be awarded £50 million were speculation but it seemed a reasonable figure in such a case.