London mayoral election: How has Sadiq Khan's Ulez and other green policies helped the capital?

Mayor of London Sadiq Khan’s transport policies are put to the test (PA)
Mayor of London Sadiq Khan’s transport policies are put to the test (PA)

Sadiq Khan likes to portray himself as the “greenest mayor ever”.

But how much of a difference has his flagship policy, the Ulez, made to air quality?

Has its controversial expansion to the Greater London boundary last August put his re-election in jeopardy?

And could the Silvertown tunnel opening in summer next year - and the linked tolling of the Blackwall tunnel - open up a new battle with the capital’s drivers?

Is the air cleaner?

In a word: yes. The London Air website, run by Imperial College, showed the capital covered in more than 50 red dots in 2016 — areas where pollution exceeded the recommended limits. By last year there were 12.

The Clean Air in London campaign group was so impressed it gave Mr Khan an A-rating for clean air in his second term — making him the first mayor to achieve the top score.

Transport for London’s target is to reduce roadside nitrogen dioxide by 60 to 70 per cent between 2016 and 2040.

By 2022 — prior to the Greater London Ulez — this had been reduced by 58 per cent (from 92 µg/m3 — micrograms per cubic metre — in 2016 to 39 µg/m3) in central London, and by 47 per cent in inner London (the boundary of the North and South circulars, from 61 µg/m3 to 32 µg/m3).

What impact has the London-wide Ulez had on air quality? We won’t know until after the election, when TfL will publish its first official figures. Tory mayoral candidate Susan Hall, who wants to scrap the expansion, has accused Mr Khan of “hiding” the data.

 (Evening Standard)
(Evening Standard)

But Clean Air in London has looked at provisional data from 16 air quality monitors in outer London and says nitrogen dioxide levels appear to be “significantly” lower.

The data, which is unverified, could also have been influenced by factors such as the weather or cleaner buses. A 90 per cent fall in Londoners buying new diesel cars will also have made a difference.

Simon Birkett, founder and director of Clean Air in London, said: “Provisional monitoring data shows that average concentrations of NO2, a toxic gas, at roadsides in outer London were significantly lower in the first six months after Ulez expansion than in the comparable period in 2022-2023.”

Oli Lord, of the Clean Cities Campaign, said: “The improvements we have seen in air quality have been remarkable.”

What we do know about the Ulez expansion is that it has helped to get rid of “old bangers”. By December, 95.8 per cent of vehicles spotted by Ulez cameras complied with the emission rules. This included 96.7 per cent of cars but only 87.8 per cent of vans.

An air quality monitor hunt in Regent Street in central London (AFP via Getty Images)
An air quality monitor hunt in Regent Street in central London (AFP via Getty Images)

Nicholas Lyes, policy director at IAM RoadSmart, said: “It’s probably too early to say whether it’s been successful. The ultimate aim is to improve air quality. But there are so many variables we will have to give it a little more time.

“I think the mayor, when he introduced the policy, was probably caught out a little bit by some of the strength of feeling against it, especially in the outer boroughs. People in the outer boroughs are more reliant on their vehicles for private use.

“The intention was a good one. But it’s been very difficult for thousands of small business and those on low incomes who are more likely to have a non-compliant vehicle.”

What the data also shows is that Ulez has not discouraged Londoners from driving — it’s just got them into cleaner cars. Traffic counts are higher than pre-pandemic, and jams — as measured by bus speeds — are worse.

The manifesto and the book

It may seem inconceivable now, but not a word of Mr Khan’s 2021 election manifesto flagged the possibility of Ulez being expanded across all 33 London boroughs. His plan was simply to expand it from central London to the inner suburbs, which he did in October 2021.

Much of the current election campaign has involved Mr Khan and Ms Hall rowing about what he plans to do next. His new manifesto categorically rules out moving to pay-per-mile road charging.

But Ms Hall doesn’t believe him, not least because his book Breathe, published less than a year ago, mentions Mr Khan’s wish to “go further” to tackle toxic air.

“We need to go further. And we intend to,” he wrote. “We have plans … to introduce a new, more comprehensive road-user charging system, to be implemented by the end of the decade at the latest.”

A couple of months after his book was published, TfL began consulting Londoners on the Londonwide Ulez.

The outcry was such that Mr Khan performed the biggest U-turn of his career. He now insists that pay-per-mile road charging is “not on my agenda”.

“As long as I am mayor, we’re not going to have pay-per-mile,” he told the London Assembly last year. “Road user charging, is off the table, it’s not on my radar, it’s not on the agenda.”

This may have been politically necessary – but, say experts, is not good news for future efforts to improve the environment.

Ulez finances

By the end of February, TfL had raised £106.8million from the daily Ulez levy, and a further £32.3million in penalty tickets. About 45,000 drivers a day paid the Ulez in December — down from almost 52,000 in October.

By the end of the year, more than 650,000 drivers had received an £180 fine for failing to pay the levy.

Since the Ulez was first launched in central London in April 2019, about £395million has been spent on start-up costs, including an estimated £115million to widen the zone in 2021 and a further £150million to take it London-wide last year.

That excludes the cost of replacing about 1,000 vandalised cameras, which TfL refuses to disclose. The bigger political question for Mr Khan is: was it worth it? He will soon have his answer.

Ulez legacy

The hostile reaction to the London-wide Ulez included widespread vandalism, fears for Mr Khan’s personal safety and his biggest U-turn as Mayor.

Pay-per-mile road charging has been ditched, despite being seen by many environmentalists as fairer — and necessary to enable London to hit the mayor’s own air quality targets.

Jon Tabbush, senior researcher at the Centre for London think tank, said Mr Khan had “spent a great deal of political capital” in the way he handled the Ulez expansion.

“It’s probably made road user charging, the long-term goal, harder to argue for,” he added. “It’s a massive shame.”

Lib-Dem assembly member Caroline Pidgeon said: “Most Londoners support cleaning up the air in London, but you have got to bring people with you. If [Mr Khan] stopped thinking he had the monopoly on good ideas and listened to others — we suggested a longer lead-in time and a scrappage scheme that was open to everybody from day one — that would have helped him hugely. It was badly managed and rushed.”

Asked if the Ulez expansion was a “success”, Ed Miliband, the shadow climate change secretary and Mr Khan’s friend, would only say: “I think it has shown that we can cut toxic air pollution.”

Nor would he propose the Ulez as a model for mayors of other cities to adopt.

Mr Miliband, during a visit to a Stoke Newington secondary school, told the Standard: “I have two teenage kids. I don’t want them breathing in dirty air. I don’t think it would be the right thing to do to get rid of this policy.

“I don’t think people should be in any kind of doubt about why Sadiq made this decision: because of the silent killer of air pollution.”

Silviya Barrett, of the Campaign for Better Transport, said: “We are pleased that the Ulez got implemented, but disappointed that distance-based road user charging has been ruled out.

“It could have been fairer than the Ulez and the combination of other charges, especially with tolls coming [next year] for the Silvertown tunnel and the Blackwall tunnel.”

Could the Ulez expansion jeopardise Mr Khan’s hopes of a third term? All the polls suggest he has a commanding lead and is on course for victory.

“I think the challenge around Ulez is that it has been weaponised by some individuals,” Caroline Pidgeon said. “The aggression around it, and the vandalism of the cameras, is not good for anything.”

By the start of March, more than 123,000 Londoners had applied for TfL grants to scrap non-compliant vehicles.

Just under 50,000 applications had been approved – with about £170m of a £210m pot of cash allocated.

About £100m of the total has been used to subsidise the scrapping of about 15,000 vans. Yet thousands of motorists face disappointment when the money runs out.

At first, Mr Khan limited access to the scrappage scheme to Londoners on benefits. With take-up weak, he eventually widened it to all Londoners with a non-compliant vehicle – but many “early adopters” will have upgraded their car without a penny of help from TfL.


According to the London Cycling Campaign, cycling is now a “mainstream” activity in the capital, with 1.26 million weekday journeys made by bike — equivalent to a third of weekday Tube journeys.

But the death of LSE PhD student Cheistha Kochhar, in collision with a bin lorry as she rode a Forest rental e-bike in Clerkenwell Road on March 19, was a horrific reminder of the dangers on two wheels.

The number of cycle lanes has quadrupled since 2016, from 56 miles to 223 miles, but not all are segregated. Road danger remains the biggest disincentive to cycling in London. TfL is falling increasingly behind in terms of achieving the Mayor’s “vision zero” target of eradicating road deaths by 2041.

Between October and December, 914 people were killed or seriously injured in road traffic collisions — well above the “maximum” target of 850. The 25 people killed included 12 pedestrians, six motorcycle riders and three cyclists.

Mr Khan says he remains committed to the “cycling revolution”, even if he’s rarely seen on two wheels himself these days.

Silvertown and Blackwall tunnels

The Silvertown road tunnel, which will link the Royal Docks and North Greenwich, is due to open in summer next year. Drivers face a toll of about £4 per trip, and the same to use the adjacent Blackwall tunnel.

Eco campaigners describe the Silvertown tunnel as Mr Khan’s dirty little secret. “What is really contradictory is that Sadiq talks about clean air but he is still building the Silvertown tunnel,” said Ms Pidgeon. “He is building a new motorway under the Thames. How does that fit with cleaning up the air?”

Mr Khan replied: “In that part of London, there aren’t enough river crossings. The Blackwall tunnel isn’t fit for purpose. That leads to children and adults breathing in poison. It’s far better than the status quo.”

As for the future, the next Mayor won’t have his (or her) problems to seek. “It’s a city of 9.7 million people now,” Mr Khan said. “It was eight million just a few years ago. If everyone jumps in their car it is a problem.”