Were environmental benefits of Sadiq Khan's ULEZ scheme exaggerated?

London mayor Sadiq Khan has been accused of attempting to “squash dissent”, after his deputy asked a City Hall-funded expert to counter science that questioned the benefits of a charge on polluting vehicles.

Shirley Rodrigues asked an academic, who was in receipt of funding from Mr Khan’s office, on two occasions to counter research and reporting about the Ultra Low Emission Zone (ULEZ) in the capital.

Ms Rodrigues asked Professor Frank Kelly whether he would be willing to “set the record straight”, after his fellow Imperial College London university academics published a study suggesting the central London ULEZ had a relatively small effect on air pollution at its launch.

Presenting the new data to climate campaigner Leo Murray, TalkTV's Ian Collins questioned the need to extend the ULEZ when air quality in the capital appears to be improving.

"Khan's office tried to fiddle with the figures," he said. "They didn't ask a lot of scientists, and they asked some scientists to change the wording of their report.

"We have the cleanest air we have had for hundreds of years. It's getting cleaner every month.

"Industry is working and functioning in a way it never has before. Homes, domestic facilities and work are functioning in a way they never have. So it is still happening. There's an organic process."

Mr Murray, director of the climate charity Possible, hit back, arguing the steady gains have only been achieved through regulations such as the ULEZ.

He said: "It's not happening anyway - all of this has happened because of regulation.

"The ULEZ is just one example of a policy driving this change. Have we all forgotten that VW and a number of other manufacturers were caught fiddling with test figures?"

An earlier study by Imperial College in 2021 found that in parts of London where a ULEZ zone was enforced, levels of deadly nitrogen dioxide fell by up to 96%.

The scrappage scheme associated with the ULEZ expansion, allowing Londoners with a non-compliant car or motorcycle to receive a grant of £2,000, opened on Monday.