Mayor of London Sadiq Khan has declared he will press ahead with extending the capital’s ultra low emission zone (Ulez) after five councils failed in their legal bid to stop him.

He described the High Court judgment as a “landmark decision” and pledged to “do everything possible” to address “any concerns Londoners may have” about the scheme’s expansion on August 29.

The outer London boroughs of Bexley, Bromley, Harrow and Hillingdon along with Surrey County Council – all led by the Conservatives – launched legal action in February over the Labour mayor’s proposals to extend Ulez beyond the North and South Circular roads to include the whole of the city.

In a ruling on Friday Mr Justice Swift dismissed the councils’ case.

Drivers of vehicles which do not meet minimum emissions standards are charged a £12.50 daily fee for entering the Ulez zone.

Transport for London (TfL) says nine out of 10 cars seen driving in outer London on an average day comply with the Ulez standards.

But figures obtained by the RAC show more than 690,000 licensed cars in the whole of London are likely to be non-compliant.

This does not take into account other types of vehicles or those which enter London from neighbouring counties.

Mr Khan said: “The decision to expand the Ulez was very difficult and not something I took lightly.”

He went on: “The Ulez has already reduced toxic nitrogen dioxide air pollution by nearly half in central London and a fifth in inner London.

“The coming expansion will see five million more Londoners being able to breathe cleaner air.”

Bromley Council’s leader, Colin Smith, claimed the judge’s decision “cannot be disguised as anything other than bitter disappointment for motorists”.

Susan Hall, the Conservative Party’s candidate for the London mayor election in May next year, said the ruling was “a shame” and reiterated her pledge to “stop the Ulez expansion on day one” if elected.

The AA urged Mr Khan to give people “more time to react” to the change or “reduce the impact on them”, while the RAC called on the mayor to give “additional support” to key workers.

But climate charity Possible described the judgment as “fantastic”, claiming Ulez expansion is “sorely needed to tackle our overreliance on cars and improve air quality”.

At a hearing earlier this month, the local authorities’ lawyers said the mayor lacked the legal power to order the expansion of the zone by varying existing regulations and argued that there was an “unfair and unlawful” approach to collecting views on the plans.

The mayor’s legal team rejected the bid to quash his November 2022 decision to extend the Ulez, arguing the move was “entirely lawful” and that “ample information” was provided for a “fair consultation”.

Giving a summary of his findings, the judge said: “I am satisfied that the mayor’s decision to expand the Ulez area by amendment of the present road charging scheme, rather than by making an entirely new … scheme, was within his powers.”

The judge added that, having “carefully considered” the consultation process, he was satisfied that enough information was given for people who wished to respond to provide “informed responses”.

In response, Mr Khan said: “I was a lawyer for more than 11 years. I’ve never seen a more one-sided judgment.”

From Monday, access to the mayor’s £110 million scheme which provides grants supporting the scrapping of non Ulez-compliant vehicles in London will be extended.

It will include all families in receipt of child benefit and every small business.

At the end of last month some £68 million remained available through the programme.

Friday’s ruling comes in the wake of last week’s Uxbridge and South Ruislip parliamentary by-election, where Labour’s failure to win ex-prime minister Boris Johnson’s seat was blamed on concerns around the expansion of Ulez.