Transport for London (TfL) has pledged to be tougher on motorists who fail to pay a fine for driving in the Ultra Low Emission Zone in non-compliant vehicles.

It says a “cohort of people” are refusing to pay Penalty Charge Notices (PCNs), resulting in a “significant” debt amounting to more than £370m.

He will tackle the problem by recruiting people to work on his investigation team and using bailiffs and wheel clamps to target these repeat offenders.

TfL will triple the size of its investigation team to step up enforcement for non-payment of ultra-low emissions penalties, leading to increased use of bailiffs and clamps.

TfL said enforcement officers had already recovered £25.6 million in unpaid debts from drivers who refused to pay penalties over the last year.

It has also seized more than 1,400 vehicles belonging to “persistent non-payers” in the past 12 months and generated more than £700,000 from the sale of their engines.

Yet the latest figures show there is still £370m of outstanding debts from unpaid PCNs.

In a letter to Mayor Sadiq Khan, the London Assembly called for the collection of these penalties to be accelerated to allow investment in wider public transport services in the capital.

Over the summer, Mr Khan refused to rule out sending bailiffs to pursue unpaid ULEZ fines after revealing more than a million PCNs were outstanding.

On Wednesday, TfL confirmed plans to triple the size of its investigation team to “strengthen work with law enforcement officers to target those in polluting vehicles and refusing to pay daily charges “.

In doing so, it will also increase the use of other enforcement measures, including the ability for bailiffs to attend a fraudster’s address, block vehicles and seize engines before selling them at auction to recover their debts.

“This is in addition to the additional costs that fraudsters accrue when they do not pay the fine within the legal deadline,” she said in a statement on Wednesday.

The increased enforcement of ULEZ taxes comes despite TfL’s claims that “more than 96 per cent” of vehicles operating in the area comply with emissions standards.

There has been a dramatic increase in reports of motorists using tactics to evade the £12.50 per day ULEZ charge and refusing to pay PCNs issued for failure to pay since Mayor Khan widened the zone on August 29 2023 to cover all districts of the capital.

Penalties for non-payment of fees are £180 – although this is halved to £90 if paid within a fortnight.

If the registered keeper of a vehicle fails to pay the PCN, it is recorded as an unpaid debt and an order is made for its recovery.

This will then result in a court issued warrant and enforcement action to recover unpaid fees.

If a motorist chooses to ignore a warrant, bailiffs are sent to the registered owner’s address to collect the money owed.

Motorists identified as persistently in default of paying the ULEZ PCNS may have their vehicle seized. The cars can then be sold at auction to recover the outstanding debt.

ULEZ escapee hit with £16,000 bill for unpaid PCN

In July, a driver with 45 warrants for his arrest was traced by TfL officers to a new address, the department said.

They claimed they no longer owned the vehicle, but TfL’s investigation team established that the PCNs were received before the vehicle was sold.

The driver paid his balance which was almost £16,000.

Another repeat offender with 21 warrants out for his vehicle was repeatedly visited by TfL enforcement officers and made a series of payments to settle his outstanding debt of more than £7,800, he indicated.

The increased enforcement of ULEZ taxes comes despite TfL’s claims that “over 96%” of vehicles meet the emissions standards required to avoid the £12.50-a-day charge.

Enforcement agents also have the power to seize specific assets of the debtor and use the proceeds to settle any outstanding debt.

In August, a car was located, seized and removed after ignoring ten arrest warrants.

The driver in question had received a total of 43 letters and had already been visited five times by bailiffs.

Between August 2023 and July 2024, 1,429 cars were seized and evacuated by bailiffs.

Some 761 of these engines – more than half (53 percent) – were sold at auction.

They generated a total of £710,147, which TfL said was spent on debts accumulated over the past 12 months.

Alex Williams, TfL’s director of customer and strategy, said: “We want to send a clear message to vehicle owners that if you receive a penalty for driving in the zone, you should not ignore it.

“Your penalty will be passed to enforcement officers to recover any fines you owe, and there is a risk that your vehicle and other property may be removed.”

As TfL promises to get tougher on repeat offenders, it is also set to launch a pilot to offer more support to vulnerable people facing sanctions in the coming months.

The program will include new guidance for TfL staff to help people in difficulty, for example by referring to a partner organization that provides financial advice.