Mother of the year Britney Spears

Britney Spears' lawyer is allegedly threatening to quit the singer's custody battle, it has been reported.The singer's attorney Laura Wasser is planning to resign in the midst of Britney's bitter legal fight with ex-husband Kevin Federline. A source told gossip website TMZ.com: "Laura has put Britney in touch with other lawyers who could help her in her ongoing custody battle with Kevin, but Britney has become so reliant on Laura she doesn't like any of the alternatives. Britney will be devastated if she and Laura part company. This could be a real blow to her case."Wasser, who has previously worked for Angelina Jolie and Nick Lachey, represented Britney in her divorce from Kevin, which was completed last month.The lawyer won Britney equal custody of the couple's sons, 23-month-old Sean Preston and 10-month-old Jayden James.The singer was seen fleeing from Wasser's office in tears last week after a meeting to discuss the case. Kevin is demanding full custody of their sons and Wasser is believed to have warned Britney to put and end to her wild partying and bizarre behaviour or risk losing her children.The 25-year-old singer is now said to be compiling a dossier of information about her ex-husband in a bid to convince the courts she should have her sons full-time.A source said: "It's not just Kevin's partying and gambling, there are all sorts of things she thinks her lawyers should know about. She may not be perfect, but she is determined to show he is not a model parent either."The case is due to be heard at Los Angeles' Superior Court on September 17.