Even with the best divorce lawyers in the land, Heather Mills is never going to leave Paul McCartney on his uppers.

But it seems Sir Paul - who is worth some £800 million - clearly doesn't feel his financial future is all that secure.

The former Beatle has revealed to friends that he plans to spend half of next year on an extended world tour which could gross as much as £60 million.

Estimates of the share of McCartney's fortune Heather may come away with have ranged from £30 million to as much as £200 million.

"Paul is going on a five-month world tour at the end of next year to get over Heather. But it is also rather a convenient way of recouping the losses he will accrue in the divorce courts", said a friend last night.

As part of the divorce arrangement McCartney is also hoping to take the couple's baby Beatrice on tour with him.

Heather is said to be angered by his decision to tour, not least because the tour will ostensibly be used to promote his new album of chamber music Ecce Cor Meum (Behold My Heart), which he has dedicated to his late wife Linda.

The tour will set off during the last five months of 2007. Sir Paul and his band will head to the States, Japan and Australia and will also do some dates in Europe.

McCartney is understood to have made plans for the new tour only in recent weeks when it became more evident that the split was heading further into acrimony. McCartney only finished his last major tour in October of last year in the US.

A friend of Sir Paul's said: "Paul is going on a five-month world tour at the end of next year to get over Heather. But it is also rather a convenient way of recouping the losses he will make in the divorce courts.

"He'll take in the USA, Australia, Japan and some of Europe as well. He plans to take Beatrice with him for some of the shows, which Heather has agreed to.

"The one thing Paul uses that helps him through the bad times is his music. His tour will put a line under Heather and signify his new start in life."

Speaking publicly of how he felt for the first time since the split in recent weeks, Sir Paul said: "I'm doing fine. I am enjoying music. It's something I love to do. It's something that sustains me."

He has spoken of how the new album was dedicated to the memory of his beloved wife Linda, who died of breast cancer in 1998.

He said he poured his pain into the new album and used it as a way to overcome his sadness. "It started when Linda was alive. It has a lot of my feelings for her in it," he said.

Since his break-up with Heather in May of this year, Sir Paul has found time to complete the project which proved too painful to complete after Linda's death.

In recent months, Sir Paul has also, say friends, rediscovered his love of live music Asked about the prospect of a new world tour, McCartney's spokesman said: "No comment".