the proposals became part of the political debate in scotland. the scottish conservatives argued that the scheme was not about congestion but about raising money and the scottish national party campaigned against the charge and made it an issue in the 2003 local elections. the scottish greens supported the congestion charge. the ruling scottish labour party lost a significant number of votes at a september 2002 council by election (slipping from second to fourth place) with participants claiming that the proposed congestion charge had been a factor. on edinburgh city council, the opposition parties of the scottish conservatives, scottish liberal democrats and the scottish national party all opposed the plans. the liberal democrats had supported road charging in the scottish parliament. the scottish transport minister, iain gray, announced government support in principle for the scheme in december 2002, subject to the residents of edinburgh supporting the scheme. a referendum was offered by the city council, which unlike the original consultation, would be restricted to the residents of the city of edinburgh council area.