Sir Paul McCartney is to release the Beatles back catalogue online - helping pay for his multi-million-pound divorce from Heather Mills.

The singles and albums will be made available on iTunes in the coming months following the final divorce hearing, due to take place at the High Court in 10 days.

Ms Mills, 40, is expected to receive between £20 million and £30 million in a cash settlement following four years of marriage to McCartney, 65.

The sale of Beatles records online will be a huge windfall for Sir Paul, Ringo Starr and the families of John Lennon and George Harrison.

Containing albums such as Sergeant Pepper's Lonely Hearts Club Band, the White Album and Help!, it will be by far the most prized music catalogue released via the internet, worth up to £200 million, according to some estimates. It is expected to dominate the download charts for many months.

This could lift Ms Mills's expectation of the divorce settlement to beyond £30 million, on the basis that Sir Paul's future income should be taken into account. It raises the prospect she could appeal if she feels the judge has not considered the online deal properly.

The catalogue's online release has been hampered by legal wrangles that have now been settled. The divorce is thought to be the final obstacle. A source close to the musician told the Evening Standard today: "I reckon the Beatles catalogue will go on this year."

In a recent interview with Billboard magazine, McCartney said: "It's all happening soon. The whole thing is primed, ready to go - there's maybe one little sticking point left and I think it's being cleared up as we speak so it shouldn't be too long."

McCartney's solo catalogue has been available for download since last May but the Beatles' recordings will be far more valuable. The bitter divorce was played out over six days behind closed doors last month. Sir Paul's legal and professional expenses alone are likely to cost about £5 million.

His lawyers are understood to have argued in court that he is worth a lot less than the £825 million that has been suggested. Ms Mills, a former model who has represented herself in court, argued he was worth much more than that.

Mr Justice Bennett's judgment on 17 March - expected to be made public at least in part - is likely to take into account McCartney's earnings during their four year marriage but also his future income, which will be hugely inflated by the deal with iTunes, owned by Apple Computers.

The download agreement followed the settling of a court case last year between Apple Corps, a company formed by the Beatles to protect its music, and Apple Computers.

A further dispute between Apple Corps and the Beatles' original record label EMI over royalty payments was also settled last year, paving the way for the download of all the Beatles' records.