LATEST: Sir Paul McCartney's estranged stepsister has warned of his "explosive" temperament, apparently backing up Heather Mills' alleged claims she was abused during their marriage. The couple's impending divorce battle turned nasty in October (06) when court papers maintaining he physically abused her were leaked to the media. Now MCCartney's stepsister RUTH, who has been estranged from him for 20 years, claims the former BEATLE is subject to terrifying mood swings. She spoke out after allegations a set of taped interviews she recorded in 1994 for Beatles writer GEOFFREY GIULIANO on her stepbrother may be sold to Mills' divorce lawyers. The 46-year-old says, "I don't know the specifics of their marriage. All I would say is that Paul can be mercurial. He's like the weather, if you wait long enough, it will change from sunny to stormy. "He is a man with a huge ego who has been used to having his own way for decades. I can only speak from my first-hand experience of him and I know that he can explode in rage and then be a gentle soul the next moment. I wouldn't say he was a split personality but he can be explosive. "Paul is a legend. He's been a Beatle, a Knight, a father, a widow and a husband but he is still human. Even gods have feet of clay." MCCartney and Mills split up in May (06) after four years of marriage and began divorce proceedings in July (06).