The letter, sent as the city marks Climate Action Week, warns the prime minister that “resisting the expansion of the Ulez will harm Londoners, particularly the capital’s children”.
Included among its authors are the chief executives of groups like Greenpeace, the Campaign to Protect Rural England, and the think tank Green Alliance.
They argue the expansion is vital “to take the action we need to improve our environment and public health”.
It is the third major letter in less than a month calling on Mr Sunak to support the Ulez expansion, after some 36 scientists wrote to him, followed by a group of more than 200 doctors and hospital workers.
The Ulez, which requires non-compliant vehicles to pay a £12.50 daily charge, is expanding on August 29 to cover the whole of Greater London.
Mr Sunak has repeatedly said he is against the expansion, telling MPs earlier this month: “While we are getting on providing significant support to families with the cost of living, the Labour Mayor of London… is busily putting it up, imposing the Ulez charge against the overwhelming views of residents and businesses.”
The other organisations who have put their names to this latest letter to Mr Sunak are Friends of the Earth (England, Wales and Northern Ireland), ClientEarth, the Climate Coaltion, and the Wildlife and Countryside Link.
Responding to one of the previous letters on the topic sent to Mr Sunak, a spokesperson at the Department for the Environment, Food and Rural Affairs (DEFRA), said: “While local authorities have a responsibility to tackle air quality in their areas, the Government has delivered significant improvements in air quality at a national level since 2010, with emissions of fine particulate matter and nitrogen oxides down by 10 per cent and 45 per cent respectively – but we recognise there is more to do.
“Our Environmental Improvement Plan sets out how we will drive down emissions from domestic burning, agriculture, transport and industry, while the Air Quality Strategy sets out our expectations of local councils to improve air quality for their residents.
“Together, these measures will support progress towards our legally binding targets and deliver cleaner air for all.”
