London drivers urged to turn off engines in bid to tackle air pollution

Plans announced by Boris Johnson would see the capital's drivers encouraged by signs and volunteers to turn off their engines in traffic jams

London drivers will be encouraged by volunteers and signs to turn off their engines in traffic jams to tackle the capital's illegal air pollution levels, under plans announced by Boris Johnson on Thursday.

But campaigners accused the mayor of failing to take hard measures to cut the city's pollution problem, which has seen six sites including Oxford Street, Knightsbridge and Brixton Road already breach annual limits just weeks into 2016.