With the introduction of a £20-a-day diesel charge for London by 2019, a lot of people are concerned about the future of the fuel.

Drivers who own older diesel-powered vehicles are unlikely to have the latest emission technology fitted, and in some cases, don't have particulate filters fitted either.

These are the drivers who will be affected most by the changing regulations on diesel, because although economical, their vehicles will churn out more nitrogen oxides (NOx) than newer models.

The Government are in talks about re-introducing a scrappage scheme for older diesels, too.

However, that is little comfort to drivers who own a diesel that's over 10 years old and cannot afford to buy a new car, or people who use their older diesel vehicles for business, such as taxi drivers.

What's the counter argument?

According to the Society of Motor Manufacturers & Traders (SMMT) there are some facts people should know about diesel.

For a start, many of our most necessary vehicles are diesel-powered, from police cars and ambulances to fire engines and even military Land Rovers.

In fact, around 99% of the 4.4 million commercial vehicles in the UK run on diesel, travelling around 61 billion miles every year, meaning diesel is fundamental to our way of life.

London skyline with fumes

Venture into London for example, and you'll see just about every Uber or black cab runs on diesel because fewer stops between the pumps means more time to pick up passengers.

Since 2016, a staggering 1.3 million diesels have been registered in the UK. That's almost one in two vehicles on our roads.

Gradually, over the last 20 years, diesels have been getting greener and greener, and with the latest Euro 6 laws on emissions, many diesels are so clean they don't even qualify for the congestion charge in London.

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How are new diesels more efficient?

The SMMT says on average, diesels emit 20% less CO2 than similar petrol-powered cars, and since 2002 have saved 3.5 million tonnes of CO2 entering our atmosphere.

Many modern diesels have a plethora of clever technology fitted to them to keep our air clean. Particulate filters (DPF), which have been fitted to all diesels since 2011, are a prime example, with half of all diesels on the road having them.

These work to collect the soot particles that come out of the exhaust and remove 99% of them.

 Exhaust with fumes

Other technology contained in the latest Euro 6 generation diesel powered vehicles converts NOx (Nitrogen Oxides) into harmless nitrogen and water before it leaves the exhaust pipe.

This sort of technology works to decrease pollution in urban areas - in London, cars are only responsible for 11% of NOx, with a majority of it actually being caused by the gas that heats our homes.

Mike Hawes, chief executive of SMMT, said: "Euro 6 diesel cars on sale today are the cleanest in history. Not only have they drastically reduced or banished particulates, sulphur and carbon monoxide, but they also emit vastly lower NOx than their older counterparts - a fact recognised by London in their exemption from the Ultra Low Emission Zone that will come into force in 2019.

"Some recent reports have failed to differentiate between these much cleaner cars and vehicles of the past. This is unfair and dismissive of progress made."

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How are regulations changing?

New measures coming into place to ensure diesels are as clean and efficient as possible, will begin from September this year.

Official EU-wide testing will see cars tested in on-road conditions for the first time, to better reflect real-world driving, such as that on a motorway and stop-start traffic.

To answer the question, should people be worried, the answer is yes and no. If you buy a new Euro 6 diesel or even a Euro 5 spec, you are much less likely to incur the charges from 2019 onwards.

However, if you own a much older car, these are not aided by any particulate filters or clever emission-saving technology and therefore fall within the charge bracket.

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