Hall stepped down after imploring with Mills, the ex-wife of Sir Paul McCartney, not to speak out. He said he could not have a good relationship with newspaper editors while his client was attacking the press. He said it would be destroying years of work building up contacts.
Hall said in The Times: "My advice was that taking newspapers on was not going to end in a victory for her."
Mills gave a string of interviews yesterday to programmes including 'GMTV', ITV1's 'This Morning' and BBC News 24. She claimed that she had almost been driven to suicide by the press backlash surrounding her divorce from McCartney.
Speaking on 'GMTV', Mills told viewers: "That's why I considered killing myself, because I thought if I'm dead then she [her daughter] can be safe and she can be with her father. I have a box of evidence that is going to a certain person should anything happen to me, so if you top me off it's still going to the certain person and the truth will come out."
PR guru Max Clifford said that Mills had made "a bad situation even worse" when she compared herself with Princess Diana and Kate McCann, because there is a lot of sympathy for McCann and Princess Diana was "one of the most popular women on the planet".
Clifford told the Daily Mail: "If you use the press then you can't condemn them for using you. No one forced her to go on 'GMTV'."
The McCanns considered Phil Hall when they were searching for a PR agency to represent them after officially being named as suspects by the Portuguese police.
Mills denied being a gold digger in her interviews and claimed that the media backlash was because she had married an icon and they split up. She added that maybe if she died then she would be revered like Linda McCartney instead. She said: "Maybe if the death threats came true and I was dead, the same might happen to me."
Mills managed to win over some US TV viewers when she appeared in US reality show 'Dancing with the stars' with professional dancer Jonathan Roberts.
She claimed that she would move to the US if it wasn't for her four-year-old daughter Beatrice, who needed to be close to McCartney.
Hall is the former editor of the News of the World and Hello! Magazine, who made the switch to PR and has represented a string of high-profile clients including Millwall and West Ham football clubs.
Hall was editor of the News of the World for five years until 2000, when he was replaced by Rebekah Wade. He then moved to Hello! before a stint at the Press Association's contract publishing division and then, in 2003, he joined Trinity Mirror in an editorial development role.