Sadiq Khan's workplace tried to "silence" scientists who discovered that his ULEZ coverage had little impression on air pollution, in accordance with studies.

In an e-mail change, Shirley Rodrigues, the London Mayor’s deputy for atmosphere and vitality, advised Professor Frank Kelly that she was “really disappointed” Imperial College had publicised findings questioning the effectiveness of the scheme.

Prof Kelly, a director of the college's Environmental Research Group, which has been paid greater than £800,000 by Mr Khan’s workplace since 2021, is alleged to have subsequently agreed to difficulty a press release saying ULEZ had helped to “dramatically reduce air pollution”.

Peter Fortune, the Conservative London Assembly Member for Bexley and Bromley, advised The Telegraph: “It is unacceptable that Sadiq Khan and his deputy conspired to silence legitimate research because it would damage the Mayor’s reputation and credibility.

“Sadiq Khan has claimed he is just following the science, yet he has been using scientific advisors to protect his own interests. Science relies on open, transparent debate.”

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Bromley Council chief Colin Smith added: “When academics are paid for their research, it quite reasonably leads to questions being asked about the outcomes sought by those commissioning the work.

“Indeed, as long ago as last autumn we directly challenged Imperial as to their methodology and the conclusions of some of their research ourselves, and the revelation of these emails now serves to seriously heighten those concerns.”

The research from Imperial College's Department of Civil and Environmental Engineering, revealed within the Environmental Research Letters journal in 2021, discovered that the introduction of ULEZ in 2019 lower nitrogen dioxide by lower than three % and had insignificant results on ozone and particulate matter.

But Ms Rodrigues is alleged to have complained it was "misleading" in an e-mail to Prof Kelly on November 16 2021.

It comes as Mr Khan's controversial ULEZ is because of develop to cowl the entire of London from August 29.

It means extra drivers must cough up the £12.50 day by day cost for essentially the most polluting autos in a bid to spice up air high quality.

A spokesman for the Labour Mayor of London stated: “It is right – and standard practice across government – that we commission experts to carry out research to inform the work we do.

“Frank Kelly and the Environmental Research Group at Imperial are some of the world-leading academic institutions looking at air quality.

"It is normal and proper to work with these experts to ensure our policies are as effective as possible at dealing with issues such as the high number of deaths – up to 4,000 a year – linked to toxic air in London every year.

“The ULEZ analysis from the engineering department at Imperial only paints a partial picture, not accounting for the full lifetime impact of the scheme and only focusing on its immediate impact around its launch. It is commonplace for academic experts to disagree with how other academic studies are interpreted, as was the case here.”

Imperial College was contacted for remark.