The rift between Britney Spears and her sister Jamie Lynn just went from bad to worse. Today, Britney called her sister “a scum person” and said she had “stooped to a whole new level of low,” after Jamie Lynn did a TV interview promoting her new book. Britney accused her younger sister of exploiting their relationship to sell copies of the memoir. In her interview, a teary Jamie Lynn declared that she’s always been her sister’s biggest supporter.