Nine-tenths of car dealers are set to reassess their relationship with diesel with a review of their forecourts’ fuel profiles in 2018, according to research carried out by Cox Automotive.

Just over half of surveyed retailers told Cox that they had altered stock profiles in 2017 (54%), but that nearly nine out of ten dealers expressed an intention to do so for 2018 (87%).

The data also shows that 80% of dealers have seen a change in consumer attitudes towards diesel due to uncertainty around the fuel, and a further 86% say they expect this to continue into 2018.

The survey follows new figures released by the SMMT that show diesel car registrations fell by 22% year-on-year this September, leading to an overall reduction in new car registrations for the first time in six years.

“Concerns about the diesel market are definitely spreading among dealers,” said Philip Nothard, Head of External Relations at Cox Automotive. “It’s been a volatile 12 months, and not entirely unexpected, but this level of decline in the new car market is significant.”

Cox Automotive reports that diesel’s historically steady market share against petrol has shifted downwards in the last twelve months.

The fuel, which held a 46% market share (against petrol at 50%) in September 2016, has now moved to 40% (against 54.6% petrol).

September data from Motors.co.uk, paints a similar picture on dealer forecourts with the first signs that days to sell are starting to lengthen for diesel, up from 39 to 40 days year-on-year. In comparison, petrol variants have reduced, down from an average of 38 to 34 days.

Nothard said: “Dealers are starting to sense that diesel vehicles could become more difficult to shift.

“There are definite signs of consumer reaction to media reports on diesel, especially in regard to its environmental impacts.”

“This media attention, combined with further external factors such as taxes and city charges have all contributed to consumer interest waning.”

He added: “For dealers investing in newer models, the sentiment is more positive. New diesel cars are cleaner and have to pass strict emission tests before being sold, so they aren’t included in city charge schemes.”

Nothard said that data from Motors.co.uk had indicated that hybrid vehicles do sell quickly when offered by retailers, taking just 29 days to sell on average, compared to 80 days 12 months ago.