Has London’s ULEZ Worked? Fairness, Enforcement and What’s Next
In the first article in this series, we explained what London’s Ultra Low Emission Zone (ULEZ) actually is and how it differs from the Congestion Charge. In the second, we looked at what six years of evidence, including newly published research, tells us about its effect on health, pollution, travel habits and revenue. But the story isn’t purely one of data. The scheme remains politically contested, and questions of fairness and enforcement are still unresolved. In this final article, we look at the reception, the ongoing debate, and where the scheme goes from here.
A divided reception
Reception to the ULEZ has been sharply divided along the lines of who bears the cost versus who feels the benefit. Health campaigners have broadly welcomed the scheme, pointing to the well-documented link between toxic air and conditions such as asthma and cardiovascular disease. The case of Ella Kissi-Debrah, the nine-year-old whose death was formally linked to air pollution exposure, became a rallying point for supporters.
Opposition has centred on cost and fairness, particularly ahead of the 2023 outer London expansion. Several outer London boroughs, with less public transport coverage than inner London, argued the charge would disproportionately hit residents who depend on their cars. Five Conservative-led councils brought a judicial review against the expansion, which the High Court dismissed in July 2023.1 Critics have also characterised the scheme as a revenue-raising exercise, which TfL and City Hall consistently dispute.
Mayor Sadiq Khan, writing about the scheme last month, has described it as the hardest decision of his mayoralty, noting that all the main political parties, including his own, initially opposed it. That’s the Mayor’s own account of the scheme’s political journey rather than a neutral assessment, but it’s a useful marker of how far the political weather has shifted: much of the cross-party opposition that existed at launch has since softened.
The enforcement question
Unpaid fines have become a genuine financial and administrative issue for TfL. As of September 2024, TfL was owed an estimated £376 million in unpaid Penalty Charge Notices (PCNs), prompting scrutiny from the London Assembly’s Budget and Performance Committee over collection practices and the sustainability of relying on this revenue stream.2 This sits alongside the broader fairness debate: the disproportionate impact on lower-income drivers in areas with weaker public transport links remains a live political argument rather than a settled one.
Independent academic research also cautions against treating the ULEZ as a complete solution. A study in npj Clean Air found no statistically significant benefit for PM2.5 specifically, and concluded that other pollution sources, such as domestic heating, also need addressing for London to reliably meet air quality guidelines.3
What’s next
Sadiq Khan has ruled out further geographic expansion while he remains Mayor, since August 2023 already covers the whole of Greater London. Future changes are more likely to involve tightening emissions standards as the vehicle fleet modernises, or broader road pricing reform, with earlier consultations having floated replacing the current patchwork of charges with a single scheme based on distance driven and vehicle type, though no firm timetable has been confirmed.4 Separately, London’s experience is increasingly being watched internationally, with cities elsewhere weighing up similar schemes but often more cautious about the political risk involved.
Outlook
Taken together, the evidence across this series supports the conclusion that London’s ULEZ has done what it was primarily designed to do: it has measurably reduced pollution and improved child lung health and public health outcomes, faster than many expected, without the economic fallout many predicted. Where the picture is less clear-cut is fairness and enforcement, and that’s likely to remain the central argument as the scheme matures.
How 2EA Can Help
Vehicle emissions zones are one visible part of a much wider compliance and reporting landscape UK businesses now operate within. For organisations working out how transport and fleet emissions feed into wider carbon reporting obligations, such as Streamlined Energy and Carbon Reporting (SECR), 2EA can help make sense of what needs to be measured and disclosed.
Sources
- House of Commons Library, “Clean Air Zones, Low Emission Zones and the London ULEZ” (CBP-9816): https://commonslibrary.parliament.uk/research-briefings/cbp-9816/
- London Assembly, “ULEZ charges and fines” (Mayor’s Question Time answer): https://www.london.gov.uk/who-we-are/what-london-assembly-does/questions-mayor/find-an-answer/ulez-charges-and-fines
- “Further improvement in London’s air quality demands more than the Ultra Low Emission Zone policy,” npj Clean Air (2025): https://www.nature.com/articles/s44407-025-00030-9
- Mayor of London / London City Hall, “The Ultra Low Emission Zone (ULEZ) for London”: https://www.london.gov.uk/programmes-strategies/environment-and-climate-change/pollution-and-air-quality/ultra-low-emission-zone-ulez-london
