Secrets of Macca divorce deal to be made public ... and Heather gets less than she wanted

Mr Justice Bennett has warned McCartney he is planning to make his judgment public because of the "overwhelming interest" the divorce case has attracted.

Sources close to the case have said they expect Ms Mills, a former glamour model, to receive between £20 million and £30 million - a huge sum but still far less than some estimates.

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The figure is significantly less than the £55million Ms Miss reportedly expected to receive.

The decision to make the settlement public is a highly unusual move which could embarrass the ex-Beatle but it will end wild speculation over the size of Ms Mills's payout.

One source close to the case said today: "The judge is considering making his judgment public.

"He feels there has been so much speculation that it would be in the public interest to end all the rumours. He has told McCartney and Mills he is considering doing that."

A separate source confirmed Mr Justice Bennett's plan to make his judgment public at a hearing provisionally set for 17 March at the Royal Courts of Justice.

The source suggested Mr Justice Bennett may produce two judgments - one for the public which avoids all mention of provision for the couple's four-year-old daughter, and a full version for Sir Paul, Ms Mills and their legal advisers.

The sources said a major sticking point during the six-day High Court hearing this month centred on just how long the couple had lived together.

Sir Paul's lawyers argued Ms Mills deserved a payout based only on his earnings during their four-year marriage.

Ms Mills, who represented herself in the High Court, claimed that calculations should be made based on the six years beginning from when they first started seeing each other.

The other major area of contention was McCartney's actual wealth and his earnings during the period he was with Ms Mills.

Rich lists claim he is worth £825million, he claims it is much less and Ms Mills suspects he is worth more than £1billion.

The judge will have to weigh up which analysis of Sir Paul's wealth is the more accurate, using it as a basis for a final settlement.

A legal source said Mr Justice Bennett has indicated Ms Mills should receive 50 per cent of his earnings for either the four years of their marriage or the six years of their relationship.

The source said: "If the judge decides McCartney's profits rose by £60 million during their time together then Mills gets £30 million. If it has gone up by £300 million then she stands to gain £150million.

"I think it's likely she will get £20 million to £30 million."

The decision to make the settlement public - although highly unusual - is not without precedent.

Mr Justice Bennett made public a 24-page judgment in which he ordered advertising and marketing magnate Sir Martin Sorrell, worth £75 million, to pay his ex-wife almost £30million, including a £ 23.4million lump sum and a £3.25million home in Knightsbridge.

A spokesman for Sir Paul refused to comment today and a spokeswoman for Ms Mills, based in Los Angeles, refused to speak.