Currently reading: Diesel sales set to slump due to pollution fears - Autocar investigation
Autocar-backed research shows concerns over diesel emissions could boost hybrid and electric sales

The demand for diesel cars is set to slump due to concerns over emissions and pollution, according to a survey commissioned by Autocar, with more than a sixth of all motorists planning to buy a hybrid or electric car next.

In the wake of ongoing controversy about emissions and the Volkswagen Dieselgate scandal, Autocar teamed up with leading survey research advisor Simpson Carpenter to conduct a study on the attitude of motorists towards diesel engines. More than 1000 interviews were undertaken for the study in May.

Diesel engines: your questions answered

The results show that despite diesels currently accounting for around four in 10 cars on UK roads, just 23% of motorists plan to buy a diesel as their next car. Notably, more than half of all current diesel owners plan to switch to another fuel type.

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The survey results showed that diesel owners currently comprise 38% of UK motorists, while just 2% of motorists owned a hybrid or electric machine.

But when asked what type of engine their next car was most likely to be powered by, less than one in four said they intended to buy a diesel. That drop contrasts sharply with a surge in demand for battery cars – 17% of motorists say their next car will be hybrid or electric-powered.


The survey also shows that current diesel owners are turning away from the engine format. Just 46% of drivers who currently own a diesel intend to replace it with a car featuring the same engine type, while 22% say they will invest in a hybrid or electric car.


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Tom Simpson, the managing director of Simpson Carpenter, said: “Car owners are predicting a major change in their buying behaviour. If they follow through on these intentions, it will give the industry a real headache.”

The survey results are backed by the most recent sales figures from the Society of Motor Manufacturers & Traders (SMMT), which showed diesel registrations in May 2017 fell 20% year-on-year. A total of 81,489 diesels were registered in May, compared with more than 101,000 in the same month last year.

According to our survey, the fall in diesel demand will be seen in both the new and used car markets. Of those surveyed who currently drive a used car, 36% run diesels – but just 23% of those intending to buy used next time say they will buy a diesel.

Simpson noted that purchase intentions often differ from actual buying behaviour, and that the relatively limited supply of new and used hybrid and EV cars could be a constraint on any extra demand.

Emissions concerns key to diesel demand slump

When asked which engine types they had entirely rejected for their next car, 30% of motorists said they had ruled out a diesel engine. 

The only engine type to be ruled out by more buyers was electric (32%). Just 15% of motorists said they had rejected hybrid cars.

When those motorists who said they had ruled out buying a diesel engine were asked for their reasons why, a massive 73% cited concerns over higher levels of pollution and emissions, and 41% citing future resale values.


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Diesels were also seen as substantially more harmful to the environment than petrol engines, and as emitting the most CO2 and NOx. When asked about specifically about Euro 6-standard cars, 47% of respondents said that diesels were a little or a lot worse for CO2 emissions than petrol engines. Just 18% thought that petrol cars emitted more CO2.

Simpson said the survey results highlighted misunderstanding over the emissions of petrol and diesel-engined cars. “Right now there’s a lot of confusion in the market about diesel cars’ impact on the environment – they’re widely thought of as more harmful to the environment than petrol".

“As well as being seen as worse than petrol for NOx and particulates, they’re wrongly blamed for emitting more CO2 than petrol. The fact that this holds true even for diesel owners’ views about Euro 6 cars shows the extent of this confusion.”

Simpson noted that the high level of concern over diesel resale values – linked to the falling demand for the engine type – could also significantly impact the market.

He added: “Concern about future resale values is very important – and it’s a fear that can affect those who are less concerned about the environment and spread the move away from diesel.”

Motorists still opposed to diesel penalties

Although motorists are moving away from diesel engines, there is still a high level of resistance to introducing measures that penalise diesel owners. 

The survey asked motorists to show their support or opposition for four measures to reduce air pollution: banning older diesels from city centres, higher in-city congestion charges for older diesels, increased tax on diesel fuels and banning all diesels from city centres.

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The only measure that received a majority of support was banning older diesels from city centres, which was backed by 56% of motorists – while being opposed by 44%.

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Of those polled, 68% were opposed to banning all diesels from city centres (with 33% in favour), 60% were opposed to increasing tax on diesel fuel and 55% were against higher city congestion charges for older diesels.


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Related to that, when asked to cite the most polluting vehicle types in major city centres, private diesel engines were only ranked fourth, behind delivery vans and trucks, buses and taxis.

Simpson said: “A chink of light is that people blame commercial vehicles, buses and taxis more than diesel cars for the high levels of pollution in city centres, which goes some way to explain the limited support for measures penalising diesel drivers.”

Support for diesel scrappage scheme

The respondents to the survey backed the prospect of a scrappage scheme for owners of older diesel cars, with 74% giving their support for one that encouraged drivers of such cars to trade them in for machines that meet the latest emission standards. 28% opposed or strongly opposed such a scheme.

The introduction of a scrappage scheme limited to people in major urban areas was supported was supported by 57% of motorists, with 63% supporting one for those who replaced an older diesel with an electric car.

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How the survey was done

Simpson Carpenter conducted 1028 online interviews with a sample of British car owners between 12 May and 22 May. Quota controls were imposed and data weighted to ensure the sample was representative in terms of fuel type, engine size and age of car.

The industry response

The SMMT responded to the survey by highlighting the ongoing attributes and popularity of the latest Euro 6-standard diesel engines on sale.

“Diesel cars continue to be a popular choice for consumers in the UK," said Tamzen Isacsson, SMMT Director of Communications and International.

"Almost one in every two new cars registered is a diesel, with buyers valuing their high performance and low fuel consumption. In 2016 more diesel cars were registered than ever before and March 2017 was the biggest ever month for diesel purchases. Manufacturers are investing billions to develop a range of low-emissions technologies to give consumer choice. Vehicles on sale today have never been cleaner or safer – from advanced Euro 6 diesels and petrols, to hybrids, plug-in hybrids and pure electric vehicles. Each serves a different need, reflecting the differing demands of motorists and the type of journeys they undertake.” 

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James Attwood

James Attwood, digital editor
Title: Acting magazine editor

James is Autocar's acting magazine editor. Having served in that role since June 2023, he is in charge of the day-to-day running of the world's oldest car magazine, and regularly interviews some of the biggest names in the industry to secure news and features, such as his world exclusive look into production of Volkswagen currywurst. Really.

Before first joining Autocar in 2017, James spent more than a decade in motorsport journalist, working on Autosport,, F1 Racing and Motorsport News, covering everything from club rallying to top-level international events. He also spent 18 months running Move Electric, Haymarket's e-mobility title, where he developed knowledge of the e-bike and e-scooter markets. 

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Ski Kid 20 July 2017

not many people understand figures

The car manufacturers are pouring out more high powwered small capacity petrol engines which will in turn become contoversial due to their emissions of even smaller soot particles than diesel so this has notr hit the fan yet,consequently the small cars up to 2 litre will go back tp petrol short term,diesels atre costinfg more due to emissions etc  the add blue system etc.So it is obvious foer under 2 litre it will revert to petrol again especially up to 1600cc non suv small makes you lugh thinking of China wanting all electric asap when they pollute like hell with dirty coal generation for their grid. Don't worry as all are bad electric  ,petrol and diesel , I think legs are good , but just a bit slow ,especially pulling a caravan or boat.


yvesferrer 28 June 2017


Choices are largely dictated by what people can afford: when the cost of petrol or diesel is at the whim of the Chancellor of the Exchequer it is easy to see why certain options find favour at any given time. Taxi drivers don't run petrol engines because they get better mileage per Pound with diesel, for instance...
Now, when electric vehicles are viable (in terms of infrastructure, overall electricity production costs, battery recycling programmes, etc.) and not just in debatable 'ranges per charge', we can have a proper discussion.
For now we have to accept the dubious statistics put out by one side or the other depending on their vested interests: hardly the way to make truly informed choices!
Carmad3 28 June 2017

Myths on Diesel

The latest diesel engines are actually cleaner than petrol and produce zero CO2 and very little NOX2. The public should continue to but diesels as they not only are far cleaner they are also more economical and will lat longer than any petrol engine. Meaning they are kinder to the environment in many ways. The bad press diesel have had recently is very unfair and inaccurate
Carmad3 28 June 2017


I mean to type continue to buy and they will last longer.