Campaigners have threatened the Mayor with legal action if he goes ahead with plans to scrap the western extension of the congestion charge zone on Christmas Eve.
Members of Clean Air in London, a not-for-profit organisation behind a three-year campaign to improve the capital's air quality, have written to Boris Johnson claiming they will push for a judicial review if the removal of the extension proceeds as planned.
The letter claims the proposals are “unlawful” and threatens legal action over the zone's removal unless immediate measures are taken to tackle any damage to air quality from the expected 12 per cent rise in traffic.
CAL is being represented by law firm Harrison Grant, who were involved in the successful opposition to the proposed third runway at Heathrow.
EU law requires action be taken to ensure levels of dangerous airborne pollutants do not exceed World Health Organisation standards in outdoor public spaces.
A TfL report to the Mayor, obtained through a freedom of information request, predicts further three to four per cent rises for nitrous oxides and particulates in the western extension if regulations are removed.