Paul McCartney attempted to pull off a high-risk legal stunt yesterday by abandoning a record £55million divorce deal just hours before it was due to be signed in the High Court.

The turn-around came late on Sunday evening after Fiona Shackleton and Nicholas Mostyn QC - Sir Paul's legal team - advised him he could save millions by letting High Court judge Mr Justice Bennett decide on a payout for Heather Mills.

The pair had yesterday been due to sign the consensual deal in the Royal Courts of Justice which would have seen Miss Mills take a £20million settlement and £2.5million a year for the next 14 years.

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Sir Paul 'was disillusioned with the deal'. Miss Mills was hopeful on her way to court yesterday

They had spent all last week poring over the deal covering everything from a gagging order to security arrangements and property to the custody of their four-year-old daughter Beatrice.

Miss Mills turned up fully hoping the deal would be signed shortly after 9am yesterday.

Soon after that she learned that there had been a major change of tack and that Sir Paul would not be coming to court to sign the settlement after all.

Miss Mills, who sources say had been celebrating the imminent deal all weekend, was said to be "incandescent with rage" after realising Sir Paul and his legal advisers had "stood her up" at court.

She put a brave face on the decision as she left court later in the day.

Her estranged husband is understood to have spent the day in rehearsals for the Brit Awards. He is due to pick up a lifetime achievement award at the ceremony at Earls Court on Wednesday.

Miss Mills will now face an agonising wait to discover how much of Sir Paul's £825million fortune she will be awarded after Mr Justice Bennett ruled yesterday that in the peculiar circumstances, he would be reserving his judgment.

The pair may not know of his decision for another month - or it may take as little as a few days.

It will be passed on to the couple through their lawyers so they may not have to return to court.

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No sign of Macca: Arriving at court, Heather Mills (left) has been representing herself when questioned by Sir Paul McCartney's lawyer Fiona Shackleton (right)

The decision to pull out of a deal as this stage might be a risky strategy for 65-yearold Sir Paul.

Miss Mills, 40, might win grounds to appeal the judge's decision. If that happens, the whole divorce could be played out in the Court of Appeal and will be open to the public.

An insider said yesterday: "Paul pulled the plug very late in the day. Heather is devastated.

"Paul is the one with the fabulously successful legal team and Heather has been working on her wits alone. For them to pull off a stunt like this, they must think they are in a strong position.

"They spent all week in court and Heather perhaps unwittingly spent the week showing her hand.

"Paul's team now look to have played a very clever game, saying 'we'll settle, we'll settle'.

"His team basically now know the worst of what she can throw at him in court. They smoked out the worst she had."

The source went on: "They are pulling the plug on it because they think the judge may well agree Heather deserves less than the £55million.

"Shackleton and Mostyn clearly think it's a risk worth taking. And if Paul gets a lower settlement and Heather does win the right to appeal, they now know the worst of what she can throw at them is not much more than has become public anyway."

The source added: "Paul was going along with everything all last week. But over the week he was becoming gradually more disillusioned by what was being agreed.

"It was he who pulled the plug. Heather was desperate to settle and had been convinced they had been in total agreement - right up until she arrived at court."

Miss Mills - who is representing herself - spent the morning session responding to points raised by Sir Paul's team.

Shortly after 1.30pm Mr Mostyn confirmed the judge was reserving the matter. Miss Mills's legal advisor David Rosen said it would be "about a month" before the judge hands down the ruling.

Dressed in a grey skirt suit, white shirt and Stella McCartney ankle boots, Miss Mills left with her usual entourage which included personal trainer Ben Amigoni, 23.