Used diesel car prices are continuing to rise despite the recent expansion of London's Ultra-Low Emission Zone (ULEZ). That’s according to new figures from online used car marketplace Auto Trader, which has seen the price of the average five-year-old diesel car rise by almost £5,000 in a year.

The ULEZ was initially introduced in the centre of London to reduce the pollution caused by older vehicles. Covering the same area as the Congestion Charge zone, the ULEZ meant any petrol car that did not meet the Euro 4 emissions standard and any diesel car that did not meet the Euro 6 emission standard had to pay £12.50 a day to use the roads inside the zone.

As of Monday, October 25, the ULEZ was expanded to cover an area 18 times the size of the Congestion Charge zone. The same rules and charges apply, but the ULEZ now covers the roads inside the North and South Circular ring road.

Signs indicating Ultra Low Emission Zone (ULEZ) on London street

London’s mayor, Sadiq Khan, said the expanded zone would improve air quality for a greater number of Londoners, claiming “toxic” air was causing premature deaths.

“London's toxic air is a health crisis causing long-lasting harm to our children and contributing to thousands of premature deaths,” he said. “'The Ultra Low Emission Zone has already cut nitrogen dioxide pollution by nearly half in central London and the expansion of the zone on 25 October means many more Londoners across the city will enjoy the benefits of cleaner, healthier air.”

Quiet Chiswick suburb in London

The news means drivers of many diesel cars built before 2015 will have to pay the £12.50 fee to drive in a large part of London. However, Auto Trader’s commercial director, Ian Plummer, said the expansion of the ULEZ had not stopped the value of older diesel cars increasing.

“You might expect there to be a big dip in demand levels and the price of cars that are not compliant with the new ULEZ zone, but that’s not the case,” he said. “The used car market is so hot that even diesel cars over five years old are continuing to increase in price. We’re seeing this not only nationally but also in Greater London where these vehicles will incur a daily charge of £12.50.”

The news comes as prices grow across the used car market, with Auto Trader seeing prices increase year-on-year every week for around 18 months. The company claims the average price of a five-year-old diesel car has risen from £13,513 to £ 18,293 in the last 12 months.