Diesel cars used to be incredibly popular in the UK. They had plenty of public and political support, as well as several incentives that encouraged drivers to make the switch. 

However, things have changed in recent years. New emissions directives, a shift in public opinion and environmental impacts have given diesel cars a bad reputation. That means they are much less popular than they were 10-15 years ago.

So, should you still buy a diesel car in 2022? Well, many drivers have decided that the answer is no.

As of March 2022, diesel vehicles had a market share of just 5.7% - down from 25.2% in 2019. In contrast, petrol cars still held 42.6% of the market and battery-powered electric vehicles (BEV) had a 15.4% share. That had more than doubled from 7.5% in March 2021!

Drivers are turning away from diesel. It's as simple as that. More are starting their journey towards an electric car or trusting petrol engines more. On top of that, many are well aware that diesel cars can be less environmentally friendly than other vehicles. All of these factors have contributed to the decline in diesel sales.

So, how have we got here? Where do we go next? And, most importantly, should you still buy or drive a diesel car?

In this article, you will learn:

  • Why diesel cars used to be popular
  • Why this has changed
  • How bad diesel engines are for the environment
  • Whether a petrol or diesel car is better for short journeys
  • When you should buy a diesel car
  • Why you might not want to buy a diesel car
  • And when you should think about buying an electric car instead

 

Summary

Diesel cars were popular for many years. There were a range of schemes and incentives that encouraged UK drivers to buy these vehicles. Then studies proved that diesel was worse for the environment than petrol. Combined with the fallout from the 'Dieselgate' scandal and the fact that they don't work well in urban areas or on stop-start journeys, many people moved away from diesel cars and their popularity fell. The only drivers that see the need for diesel are high-mileage ones that frequently cover long distances or those who tow a caravan or trailer.

With the introduction of more restrictions set to affect diesel cars in 2022 and beyond, many drivers are asking: "Why should I buy a diesel car and not switch to an electric vehicle instead?" And, if an electric car is right for you, there's no reason not to make the switch this year.

 

Why Were Diesel Cars So Popular? (And What Changed?)

For years, UK drivers were encouraged to buy diesel cars. This led to a sales boom in the 1990s and 2000s which saw diesel cars' market share peak at 55.2% as recently as 2011.

This was due to several factors:

  1. Diesel cars were estimated to produce c.20% less CO2 (Carbon Dioxide) than petrol cars.
  2. Gordon Brown introduced tax breaks for diesel cars in 2001.
  3. Car manufacturers agreed to reduce CO2 emissions by 25% over 10 years in 1998.

Unfortunately, there were other issues with diesel cars. Subsequent studies found that they produced far more NOx (Nitrogen Oxides) than petrol cars. This toxic exhaust fume is directly linked to poor air quality. In fact, in 2019, NO2 caused between 3,600 and 4,100 excess deaths in Greater London, according to an Imperial College study. Alongside VW's 'Dieselgate' scandal, this rapidly changed public perception of diesel vehicles.

 

'Dieselgate'

In 2015, Volkswagen was found to have installed a 'defeat device' to suppress the recorded levels of NOx in their diesel engines. This 'defeat device' could recognise when it was running in a lab compared to running on the road. As a result, 400,000 UK drivers were horrified to discover that their VW Group vehicles were producing 9x more NOx gases than the official figures stated.

Once 'Dieselgate' broke, 91,000 drivers took VW to court, suing them for misleading and endangering the public with unsafe NOx levels. To this day, VW has paid out around €30 million in compensation.

Not only did this scandal shock the world, but it also opened many eyes to the damaging impact of diesel cars. Many drivers felt angry that they had been encouraged to harm the environment through the schemes that the UK Government set up. 'Dieselgate' also accelerated the development of electric cars, leading to the sales boom in the last few years.

'Dieselgate' was a bad moment for diesel cars. Most people saw what Volkswagen did and decided that diesel vehicles had had their day. This was mainly due to the environmental impact they have. 

 

Are Diesel Cars Bad For the Environment?

Despite the fact that diesel was hailed as a cleaner fuel and that diesel cars produce lower levels of CO2 than petrol cars, they are very bad for the environment. The high NOx emissions make them far worse for public health than the equivalent petrol model. What's more, it's not easily avoidable as the fuel itself contributes to these problems.

Diesel doesn't combust as cleanly, or as fully, as petrol. This produces excess smoke and toxic emissions which have nowhere to go but out the exhaust. 

However, there has been a big effort to limit the effect of these emissions. All modern diesel vehicles must meet Euro 6 emissions regulations. They also have Diesel Particulate Filters (DPF) and AdBlue technology fitted as standard.

 

Diagram of a diesel particulate filter showing how every element reduces environmental impact of diesel cars

Here's how a Diesel Particulate Filter reduces the environmental impact of diesel cars.

 

 

What is Euro 6?

Euro 6 is the strictest emissions standard yet. It aims to reduce the levels of harmful exhaust emissions released into the atmosphere. While it targets both petrol and diesel cars, it mainly affects diesel vehicles.

Euro 6 means that manufacturers can only sell diesel vehicles that produce much lower levels of NOx. Euro 5 regulations allowed NOx levels of 180mg/km whereas Euro 6 allows just 80mg/km. As a result, every diesel car registered since September 2015 is as clean as possible. For comparison, the petrol limit is 60mg/km - so the gulf in environmental impact isn't as wide anymore.

Nevertheless, if you're conscious about your carbon footprint, both petrol and diesel cars are much worse than electric vehicles. If you want to reduce your environmental impact, you should consider buying an electric car in 2022 instead.

There are also several situations where driving a diesel car is even worse for the environment and your wallet than driving a petrol vehicle.

 

Is a Petrol or Diesel Car Better For Short Journeys?

A petrol car is far better for short or stop-start journeys than a diesel car. This is because the DPF can clog at slow speeds. 

And as this is one of the main ways manufacturers reduce the environmental impact of diesel vehicles, that's bad news.

A DPF traps excess exhaust emissions as soot. This reduces your car's NOx output and carbon footprint. Eventually, this soot will build to a level that affects your car's performance and the DPF will have to complete a process known as regeneration. This increases exhaust temperatures and burns the soot away cleanly. However, you need to drive at 40mph+ for around 20 minutes for it to work.

If you don't live near a motorway or other high-speed road or have no need to use them, you can end up causing more harming your diesel car. If the DPF can't regenerate, it becomes clogged and can cost over £1,000 to replace. If you don't clean away the ash and soot regularly, either through 'regeneration' or by booking a DPF clean for your diesel car, you can also fail the MOT emissions test - and this causes an automatic failure!

If you don't think that you can look after the DPF correctly, we would advise that you don't buy a diesel car in 2022.

 

Green venn diagram showing similarities and differences between electric cars, petrol and diesel cars and hybrid cars

If you haven't yet decided whether you should buy a diesel car, here's how internal combustion engines (ICE) stack up against hybrid and electric cars.

 

 

If you are looking to buy a diesel car in 2022, we suggest that you first ask yourself these questions:

  1. Do you drive in urban areas on a regular basis?
  2. Do you drive less than 12,000 miles a year?
  3. Do you do more short journeys than long distance driving?
  4. Do you do lots of stop/start journeys?

If you answer yes to one or more of these questions, you will be much better off buying a petrol or electric vehicle than a diesel one.

 

Okay, so far it may sound like diesel cars are completely irrelevant. After all, why would you buy a car that has a huge environmental impact and doesn't work well in a range of situations?

Well, they do still have their place and a 5% market share shows that some drivers are buying diesel cars in 2022. So who would benefit from driving a diesel vehicle?

 

Why Should I Buy a Diesel Car?

You might want to consider buying a diesel car if you meet any of the following criteria:

  • You drive more than 12,000 miles a year
  • You regularly drive long distances. Diesel cars are much more fuel-efficient than the equivalent petrol model at high speeds. 
  • You often tow a caravan or trailer
  • You want to buy a larger car, such as an SUV or people carrier.

 

Fuel Economy

The fuel economy of a diesel car is significantly better than the equivalent petrol model. Diesel-powered engines use less fuel during the combustion process which means that a diesel Vauxhall Corsa can achieve a staggering 88 miles per gallon! For comparison, the most fuel-efficient petrol version can only manage 69 miles per gallon. Most struggle to reach 45 miles per gallon, just half of what the diesel version can achieve.

If you're looking to improve your fuel economy over long distances, a diesel car might be the right choice for you.

 

Now if you think a diesel car would be a good option for you in 2022, that's great! It could definitely be worth driving one but you should keep one eye on the future before you make your final decision, especially if you're thinking about buying outright.

 

What Does the Future Look Like For Diesel Cars?

Manufacturers won't be able to sell brand-new petrol or diesel cars in the UK from 2030. If you buy a diesel car before 2030, it seems likely that you will still be able to sell it as a second-hand model. There is currently no legislation banning the sale of second-hand petrol and diesel cars, but there are other changes due to come in this decade that target diesel cars:

  • The Euro 7 emissions standard. This is being introduced in 2025 and will be even stricter than the current Euro 6 standard. On the other hand, it will give drivers the confidence to buy an even cleaner diesel car.
  • Increase in first year car tax for diesel vehicles. Plus, the 2018 tax changes means all older, more polluting cars will pay far more car tax.
  • Restricted access to urban areas. More towns and cities are introducing Clean Air Zones (CAZ), in an attempt to clean up air in densely populated areas. This means that many older, high-pollution vehicles have to pay to drive into these zones. There are also several Low Emissions Zones (LEZ) and Ultra-Low Emissions Zones (ULEZ) either in force or planned for 2022 and beyond.

Here's a bit more about what you need to know.

 

Clean Air Zones

Three Clean Air Zones came into force in 2021. These were:

  • Bath - All vehicles except cars and bikes have to pay if they don't meet the required emissions standards. Taxis, minibuses and vans will be charged £9 a day and all other vehicles charged £100 a day to enter.
  • Birmingham - All vehicles except motorbikes have to pay. Cars will pay £8 a day, with HGVs paying £50.
  • Portsmouth - Non-compliant buses, coaches and HGVs must pay £50 per day to drive into the city centre, while non-compliant taxis and private hire vehicles must pay £10 per day.

If you live in an area with a CAZ or other emissions zone, you can find more information on your local council website.

In 2022, Clean Air Zones are expected in the following cities:

  • Bradford
  • Bristol
  • Greater Manchester
  • Newcastle-Upon-Tyne
  • Sheffield

Other Clean Air Zones are likely throughout 2022 and beyond. We recommend that you pay attention to the local news and council website for updates in your area.

For more information about Clean Air Zones, Low Emission Zones and the London Ultra-Low Emission Zone, please see this guide: What Are Clean Air Zones? (And Where Are They?)

 

What About Second Hand Diesel Cars?

While a brand-new diesel car is slightly more expensive to buy than a petrol car, they also depreciate faster. For example, a brand-new diesel BMW M5 is only 2.3% (£990) more expensive than the petrol equivalent but the depreciation means that you can find some excellent second-hand deals.

However, some of these older models can be very polluting. Previous emissions standards weren't as strict as Euro 6, so pre-2015 reg cars can be very expensive to run. This is because of higher road tax and Clean Air Zone charges. While some manufacturers adopted emissions limiting features before they were legally required to, many didn't. This means you might want to avoid many second-hand diesel models if you're a climate-conscious buyer.

Many used car websites, such as Whatcar?, allow you to filter by emissions output so you find a clean diesel car.

 

Selling a Diesel Car

If you're looking to sell your diesel car, buyers will still pay a reasonable price. However, you might not feel comfortable selling an older, inefficent model. If you're in this situation, many manufacturers now offer 'scrappage schemes' for old diesel cars. These can knock a few thousand pounds off the cost of a new vehicle when you trade in your old one.

 

We believe that diesel vehicles still have their place in 2022. As long as you are responsible and keep them properly maintained, you can reduce their environmental impact. What's more, their fuel economy makes them very popular with high mileage, long-distance drivers and they are also popular towing vehicles.

But it's clear that diesel models are on their way out. And that means that there's one common question among drivers in 2022: should I be driving an electric car?

But what's the answer to it?

 

Should I Buy an Electric Car Instead?

Ultimately, if you're thinking about buying an electric car (EV), it must meet your driving needs. We recommend that you consider the following before you buy, lease or subscribe to an EV:

While electric cars may currently be more expensive than petrol or diesel cars, running costs are often cheaper, which helps to balance it out. That being said, we strongly recommend that you consider whether owning an electric car is right for you before making any decision.