Now the London mayor Sadiq Khan has accused the Government of “weaponising” air pollution – days before his plan to expand the city’s Ultra Low Emission Zone comes into effect.

From Tuesday, the ULEZ will include all 32 London boroughs, making it the biggest anti pollution charging zone in the world. Drivers of cars which don’t meet minimum emission standards will have to pay £12.50 a day – and that’s proving highly controversial, especially in London’s outer areas, as Kiran Moodley reports.