Autorola has reported a third consecutive quarterly rise in online used diesel prices as new car sales continue to fall.

Used diesel prices rose from £16,729 in Q2 to £19,758 in Q3, an increase of £3,029 (18.1%) despite registering the highest average age and mileage in 2021 of 34 months and 26,202 miles.

This represents a total price rise in 2021 of £4,989, reinforcing a healthy diesel demand at a time when new diesel car sales fell by 43.8% in the first nine months of the year according to the Society of Motor Manufacturers and Traders (SMMT).

Jon Mitchell, group sales director at Autorola UK, said: “With diesel new car sales falling dramatically every month it won’t take long before demand exceeds supply.

"The fewer diesels in the market the more prices will increase, until such time as diesel fuel is unavailable which looks unlikely anytime soon.

“There is still a big sector of the driving community that is not ready to go electric or even hybrid, particularly when they cover higher annual mileages or drive large SUVs.

"Rather than used diesel prices falling in the future we believe they will continue to rise.”

Overall, the average used car prices Autorola has sold online in Q3 was £16,989 at an average age and mileage of 33 months and 19,940 miles, representing an increase of 19.8% (£2,812) in the quarter.

Hybrid used volumes doubled during Q3 and prices rose to £23,268 from £17,591 (£5,677) in Q2 fuelled mainly by the average age and mileage falling by six months and 7,000 miles during that period.

Competition for used car stock continued to grow as used car retail values rose 21.4% in September to reach a new record high after 18 consecutive months of appreciation.

The online platform’s Auto Trader Retail Price Index showed that last month’s 17.2% like-for-like increase had been eclipsed by a further acceleration in price growth, raising the average price of an advertised used car to £16,067.

Record used car value increases in September have been hailed as a “black swan event” by Cap HPI, with head of valuations Derren Martin describing the seventh consecutive month of rising prices as “extraordinary”.

Market analysis from the valuations provider showed that live valuations had recorded an average 5.9% increase in values – equivalent to £860 – at three-years, 60,000-miles and said that such a rise had not been expected.