ULEZ: Watchdog criticises mayor over data transparency

The UK Statistics Authority (UKSA) says Sadiq Khan's claim that 90% of cars in outer London meet Ultra Low Emission Zone (ULEZ) standards was not supported by publicly available data at the time.

Data was released this month after a complaint was made to the watchdog.

The mayor's office admitted he misspoke in March when he said nine in 10 households complied.

City Hall's claim that 90% of cars seen driving in outer London complied with ULEZ standards was backed by the UKSA.

From 29 August, the most polluting vehicles within Greater London must pay a £12.50 daily charge or a £180 fine.

The ULEZ expansion is subject to a judicial review next month.

The limited Transport for London (TfL) data shows the daily average total number of ULEZ-compliant cars detected in outer London in November 2022 stands at 90%.

A separate freedom of information request by the BBC to TfL showed one in six cars registered in outer London did not meet ULEZ standards last year, based on figures from the Society of Motor Manufacturers and Traders.

The BBC has repeatedly requested the complete data behind the 90% claim from the mayor's office, including the number of vehicles captured on camera.

The official statistics watchdog called on the mayor to provide more details to back up the claim and said it was part of a pattern where the mayor's agency TfL made public claims without publishing supporting evidence.

The Office for Statistics Regulation (OSR), the independent regulatory arm of the UK Statistics Authority, looked at what Mr Khan has said about ULEZ after a complaint from Liberal Democrat MP for Twickenham Munira Wilson in April.

She said Mr Khan's claim about how few households would be hit by ULEZ was "misleading."

TfL said at the time that nine out of 10 cars seen on its cameras "driving in outer London on an average day" did comply with ULEZ standards.

However, Ms Wilson said this was not evidence about the number of households affected.

In his letter to Ms Wilson, UKSA chairman Sir Robert Chote said: "We are satisfied that data collected by TfL at the time supports the mayor's claim that nine in 10 cars seen driving in outer London now meet ULEZ standards.

"However, data on households in outer London who have a car that meet ULEZ emissions standards are not available.

"The statement made by the mayor relating to households in outer London is therefore not supported by publicly available data.

"The data underlying the mayor's claim on cars driving in outer London were not available to the general public at the time, either from the mayor's office or from TfL.

"Users requesting clarification were provided with additional information, but that too was not made available on an equal basis to the general public."

Sir Robert said that this was "inconsistent" with "principles of intelligent transparency" and the Code of Practice for Statistics to which the mayor and TfL voluntarily subscribe.

"This case is one of several examples raised with us in which TfL has made statements or issued press releases based on unpublished TfL data or where data quoted are not provided with sufficient context," he said.

"This prevents interested members of the public from being able to verify the figures, which can undermine trust in the organisations producing the analysis and their other outputs.

"While some additional information has now been published, I would urge the mayor and TfL to make this material fully accessible to support understanding on what is a topic of high public interest."

A spokesperson for Sadiq Khan said: "City Hall welcomes confirmation that the OSR is content with the accuracy of the statement that nine out of 10 cars seen driving on an average day in outer London are ULEZ compliant.

"We note that further background explaining the data should have been provided at the time."

Ms Wilson said the mayor "has serious questions to answer".

She said: "The case for delaying this scheme is now overwhelming. Not even the mayor knows how many households in outer London have non-compliant cars.

"We need far more openness from City Hall if the public is going to buy into this scheme."

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