Singer Dionne Warwick and former American football star O.J. SIMPSON have been named California's most prolific tax debtors. The pair have been publicly outed as part of a naming and shaming campaign by the state's tax collection agency. The sports star-turned-actor owes California $1.44 million (GBP750,000). Grammy Award-winner Warwick has been accused of having $2.67 million (GBP1.35 million) in unpaid taxes. The list comprises 250 names and the tax board hopes its publication will shame offenders into paying up. John Chiang, chair of the Franchise Tax Board, says, "Each year, California loses more than $6.5 billion in unpaid taxes. Hopefully this action will encourage these taxpayers to come forward, pay what they owe, and quickly help the Franchise Tax Board remove their names from the list."