Transport for London is promising to crack down on drivers who flout its ultra-low emission zone (Ulez) after revealing that 94% of the £790m owed in fines has been racked up by persistent offenders.
Non-payers have been fined up to £17,000 this year, including one driver whose car was seized and sold at auction after he ignored 130 warning letters and 14 visits by enforcement officers.
More than 97% of vehicles driven in the Ulez are compliant, and TfL said most people who drive more polluting, older vehicles pay the Ulez charge. A small minority of drivers with four or more penalty notices accounted for 94% of the outstanding debt, it added.
About £16.5m was recovered through enforcement in the first half of 2025, and 530 vehicles seized, with 350 sold at auction, raising £285,000. TfL said it was escalating action to county courts and, in extreme cases, to potential bankruptcy proceedings.
Tampering with enforcement cameras has been a problem in some parts of London. Photograph: Andy Hall/The Observer
Motorists driving non-compliant vehicles – typically diesels more than a decade old or petrol cars registered before 2004 – must pay a £12.50 daily charge to drive in the capital.
Nearly 2 million drivers and more than 3m vehicles are signed up to TfL’s automatic payment system for the congestion, Ulez and other road charges based on a number-plate recognition system.
The Department for Transport and the Driver and Vehicle Licensing Agency are now sharing data with TfL to track offenders and launch enforcement action.
TfL said there was a known link between deliberate evasion and other criminal activity. The government was aiming to increase powers to seize vehicles and tackle problems such as registration plate tampering.
The Ulez, which was drawn up under Boris Johnson’s mayoralty and introduced in 2019, became a totemic political issue after his successor, Sadiq Khan, expanded the zone throughout Greater London in August 2023. It was a factor in Labour’s failure to take Johnson’s former seat of Uxbridge and South Ruislip in the July 2023 byelection, although Labour triumphed there a year later in the general election.
According to City Hall’s progress reports on air quality, roadside nitrogen dioxide (NO2) concentrations are an estimated 54% lower in central London than projected had the Ulez not been introduced, and 24% lower in outer London, with other pollutants also significantly reduced.
There have, however, been numerous reports of people being incorrectly charged. Tampering with number plates and enforcement cameras has also been an issue. TfL had to rescind charges and PCNs sent to drivers in Chingford last year after vandalised cameras were turned to face the wrong way.
A number of European drivers were also issued with repeat fines by TfL, some incorrectly, after failing to pre-register vehicles with foreign number plates.
Alex Williams, TfL’s chief customer and strategy officer, said: “We know that we need bold solutions to tackle the public health crisis and poor air quality in London and Ulez does just that. Only a very small minority of vehicles now don’t meet the standards. Most drivers who have vehicles that are liable for the charge are responsible and pay it. It is only a small group of persistent evaders who fail to do so.”
Williams said ignoring PCNs could mean cars or property being forfeited. He urged people who faced financial difficulties not to ignore PCNs but instead “engage with our staff, who can consider your individual circumstances and work with you”.
