Sir Paul McCartney has reportedly filed for divorce from Heather Mills, citing her "unreasonable behaviour" for the end of their four year marriage The former beatle, who has hired lawyer FIONA SHACKLETON, who represented Prince Charles in his divorce from DIANA, alleges Mills was "rude" and "argumentative" towards his employees, reports British newspaper The Sun. However the 64-year-old is keen for the dispute not to turn nasty, for the sake of the couple's two-year-old daughter BEATRICE. A source close to the family tells the newspaper, "Paul wanted a clean break for the sake of Beatrice. He was determined these details would remain private and he's very disappointed that somebody in a position of trust has revealed all." But the former model has vowed to put her side of the story across in Britain and the US. A spokeswoman for Mills says, "Heather's going to be filing her own counter claims about matters both in this country and America. Any views she has on her divorce will be handled discretely. She is hugely disappointed that matters of such a confidential nature should be aired in public and feels it is inappropriate to speak about such matters with a child involved."