Opponents of the Ulez expansion say they are "hugely disappointed" after they lost a legal bid to halt it, but others argue it will save lives.

A group of five Conservative-led councils today (July 28) lost their High Court challenge against Mayor of London Sadiq Khan’s plans to expand the capital’s ultra low emission zone (Ulez) to all of Greater London from August 29.

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

They said the mayor lacked the legal power to order the expansion by varying existing regulations and argued that there was an “unfair and unlawful” approach to collecting views.

Mr Justice Swift said the consultation on the scrappage scheme was “not in depth”, but was “lawful”.

If it goes ahead, the extended Ulez will see drivers in outer London pay a £12.50 daily fee from August 29 if their vehicles do not meet the required emissions standards.

Mr Khan described the judgment as a “landmark decision” and said he will press ahead as planned.

He said: “The decision to expand the Ulez was very difficult and not something I took lightly, and I continue to do everything possible to address any concerns Londoners may have.”

Harrow Council leader Cllr Paul Osborn called the judgement "hugely disappointing", adding: "It is a sad day for our residents and businesses who were worried about the impact the expansion will have on them when it comes into force in August.

"I firmly believe that the Ulez expansion is the wrong scheme for outer London. We had an arguable case, and the fact that we got this far in our challenge against this unpopular scheme shows we were right to proceed."

But Green Party London Assembly Member and Camden councillor Sian Berry said: "The Londonwide clean air zone will save lives, it is as simple as that.

"I’m glad the courts have backed the vital Ulez scheme, cleaning up London’s air is not a political crusade but respect for a basic human right – the right to clean air."

She added: "We must always remember that when it comes to the ULEZ we are discussing a measure that is going to save lives and avoid stunting the lungs of our children."

Conservative mayoral candidate and Harrow councillor Susan Hall said: "While it is a shame the High Court did not find the Ulez expansion to be unlawful, there is no denying that Sadiq Khan's plans will have a devastating impact on families and businesses across the city.

"If I am elected Mayor, I will stop the Ulez expansion on day one and set up a £50m pollution hotspots fund to tackle the issue where it is, instead of taxing people where it isn't."

Keith Prince AM, City Hall Conservatives' transport spokesperson, said: "While there was insufficient evidence the Ulez expansion is unlawful, the evidence is clear that the policy will hit the poorest hardest, while having only a negligible effect on air quality. Sadiq Khan cannot ignore the overwhelming opposition of both Londoners and his own party forever. We will continue campaigning to get the ULEZ expansion scrapped, so we can tackle air pollution where it is instead of taxing where it isn't."

Responding to the news that the High Court Challenge to the expansion of ULEZ has been unsuccessful, Liberal Democrat London Assembly Member and Transport Spokesperson Caroline Pidgeon said: “The Liberal Democrats have been clear throughout this saga, we support action to clean up London’s air, but this must be done with adequate financial support to help people through any changes.

“Twice in the London Assembly we have called on the Mayor to introduce a more generous scrappage scheme, yet both times Labour rejected our calls. This is despite us being in the worst cost-of-living in living memory.

“We will continue to push Sadiq Khan to introduce a more generous scrappage scheme and for a longer lead in time for the scheme to be introduced.”