ULEZ: Watchdog ‘satisfied’ with key claim, though criticises Khan for lack of transparency

An independent statistics watchdog has said it is “satisfied” with Sadiq Khan’s claim 90% of vehicles seen driving in outer London are ULEZ-compliant - though it also castigated the mayor for not making the data behind it immediately available to the public.

The mayor and Transport for London (TfL) have repeatedly referenced the figure when advocating for the planned expansion of the zone. It is currently expected to extend to cover the whole of greater London on August 29.

Separate data, from the Society of Motor Manufacturers and Traders, found one in six vehicles owned in outer London are non-compliant. However, Mr Khan has said he considers the 90% stat to be the most accurate representation of the number of vehicles likely to be exempt from paying the £12.50 daily charge, due to it including all of those seen driving, rather than simply located, in the capital’s outer boroughs.

Munira Wilson, the Liberal Democrat MP for Twickenham who recently tabled an early day motion in parliament calling for the expansion to be delayed, wrote to the UK Statistics Authority in April querying the statement.

The authority’s regulatory arm, the Office for Statistics Regulation (OSR), has since responded saying it is “satisfied” with the data.

However, it added the fact it was not made available to the general public at the time, with only additional information published when asked for directly, is “inconsistent with our principles of intelligent transparency and with the Code of Practice for Statistics”.

The OSR chair, Sir Robert Chote, wrote: “This case is one of several examples raised with us in which TfL has made statements or issued press releases based on unpublished TfL data or where data quoted are not provided with sufficient context.

“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 Mr Khan said: “City Hall welcomes confirmation that the OSR is content with the accuracy of the statement that 9 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.”

A judicial review into the mayor’s plans to expand the ULEZ is due to be heard in court next week, after a series of challenges were raised by four London Conservative councils, plus Surrey County Council.