Sales of used diesel cars increased 0.3% in 2018 to further highlight the resilience of the much-maligned fuel-type, according to data published by Auto Trader.
The online used car marketplace said in its monthly Retail Price Index report that diesel remains "consistently the fastest selling fuel type for used cars", with 67% (eight-in-12) of the monthly top fastest selling used cars powered by the fuel.
In total, 57% of the used cars featured on Auto Trader's monthly top 10 fastest selling cars lists in 2018 were diesel, it said.
Last year the rate of price growth for used diesels steadily accelerated from just 2.6% in January 2018, to 4.5% in January 2019.
At an average price of £14,514 last month, it equates to the highest rate of growth for diesel since August 2018.
Auto Trader’s commercial product director, Karolina Edwards-Smajda, said: “Fuel represents just one in five searches on our marketplace, so whilst the sustained decline in diesel is significant, it’s not representative of all consumers.
"Rather, with the percentage of fuel searches declining from 25% to 20% in just 18 months, it highlights that car buyers are becoming increasingly agnostic.
"Our research consistently shows that they’re not limiting their search to a type, but instead considering all as part of their next car journey; new, used, petrol, diesel, or electric. Retailers should be marketing to them accordingly.”
In contrast to diesel, and the widely held views of its demise, Auto Trader claimed that 2018 saw a gradual easing in the rate of growth for petrol prices.
In January 2018, petrol prices grew at a rate of 10.7%, but last month’s average price of £11,374 represented an annual like-for-like increase of just 3.7%.
While the latest industry results reported sales of second-hand alternatively fuelled vehicles (AFVs) had increased 26.9% in 2018, the Index, which combines and analyses data from over 500,000 trade used car listings every day, reported a similar slowing down of used prices as petrol last year, albeit at a less precipitous rate.
In January 2018 the rate of growth for a second-hand AFVs was 8.4%, but with an average sticker price of £21,399 last month, the rate of price growth has decreased to 4.6%.
In terms of the whole market, the average price of a used car reached £13,025 in January; which on a like-for-like basis equates to a 4.1% increase on the same period last year.
Each month, 21% of all searches on Auto Trader are based on fuel. In January, the searches attributed to diesel fell to an all-time low of 45%; the first time ever it has dropped below petrol, which at 48% of all fuel related searches, marks an all-time high.
It follows two years of steady decline for diesel searches, gradually falling from a high of 71% of all fuel related searches in November 2016. In contrast, petrol has slowly increased from 26% during the same period.
The trend was sparked following a High Court ruling which found the government’s plan for tackling the UK’s air pollution crisis was poor. Subsequent promises of a tougher stance on diesel vehicles and emissions set the negative tone of the fuel-debate, which continues today.
The trend was slow to influence AFVs on Auto Trader. Searches attributed to AFVs remained flat at 4% until July 2018, before steadily increasing to 7% in October, from where it has remained since.