The council is seeking a judicial review that will halt the scheme's introduction, claiming that Livingstone made the decision to go ahead without making a proper environmental impact assessment, did not hold a public inquiry - which is unlawful - and has ignored the human rights of people and businesses affected by the scheme.
Councillor Simon Milton, leader of the majority group on the Conservative-controlled Westminster City Council, said: 'If the scheme and its impacts had been properly considered, this action would not be necessary. If we are successful, the Mayor will be forced to consider all options for reducing congestion and ways of improving any proposed scheme prior to implementation.'
A judicial review could force a public inquiry lasting six months. However, Livingstone condemned the move as purely political, and a spokesman for Transport for London said he was confident that the challenge come to nothing and the scheme would go ahead on time next February.
TfL denies there was a need to hold an official environmental impact assessment, because such examinations are only necessary for large building projects. It claims the scheme would help fight pollution through a 10-15% reduction in traffic levels.