Livingstone introduced the London congestion charge with the purpose of reducing traffic congestion in central London. Since being introduced the charge has proved to be controversial, though Transport for London maintains that traffic has fallen by 20% within the charge zone since the scheme began. One reason for the controversy is that whilst the scheme has been lucrative for its private-sector operator, Capita, some people argue it has not made enough money for public transport because the money has been spent on other things.