A dispute between Heather Mills and her former divorce lawyers appears to have escalated as rumours flew today that both sides are considering taking legal action.

Mishcon de Reya, which famously represented Princess Diana when she divorced Prince Charles, is suing Ms Mills for up to £2 million in unpaid fees, the Daily Mirror reported.

The law firm refused to continue working for Ms Mills after she ignored repeated instructions not to discuss the details of her split from Sir Paul McCartney in the media.

Mishcon is now said to be chasing Ms Mills for 20 months of unpaid fees. The firm declined to comment.

The Daily Telegraph reported that Ms Mills was threatening to bring a counter-suit against Mishcon, although it did not say on what grounds.

Ms Mills’ spokeswoman could not be reached for comment and she refused to comment to the newspaper.

The increasingly bitter divorce battle will move towards a conclusion next week when Sir Paul and Ms Mills, who is now representing herself, will meet at a final hearing.

The five-day hearing, at the High Court before Mr Justice Benner, will decide how the warring couple will split their assets. Sir Paul’s wealth has been estimated at around £800 million.

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