Data published by the motor industry has suggested that diesel car sales dropped by 25% during January 2018 compared to the number sold during the same month in 2017.
The figures, published by the Society of Motor Manufacturers and Traders (SMMT) suggest that 58,703 new diesel cars were registered for sale during the first month of the year, down from 78,905 12 months ago.
In comparison, petrol car registrations have increased, rising from 88,380 in January 2017, to 95,892 this year. In 2017, diesel car registrations dropped by over 17% compared to the year before.
Growth in alternatively fuelled vehicles has also continued, with 9,020 registered during January, 23.9% more than during the same month in 2017. However, they still represent only a small proportion of the total vehicles registered for sale, at 5.5%.
While anti-diesel campaigners will most likely welcome the continuing decline in diesel as positive news for the UKâ€™s air quality, others may view the trend in a different light.
Diesel vehicles have been recognised as a major contributor to nitrogen dioxide pollution on busy roads across the UK, particularly as some diesels have been found to be emitting far higher levels of pollutants in real-world conditions than in laboratory tests to determine if they should be allowed on the road.
However, declining diesel sales are also likely to impact the carbon tailpipe emissions of new cars, potentially hampering progress towards climate change targets.
Diesel vehicles are known to emit lower levels of CO2 than petrol vehicles, thus helping to reduce the impact of transport on climate change, and have therefore enjoyed favourable taxation rates compared to petrol cars.
And, others have suggested that that figures suggest that car buyers have â€˜gone on strikeâ€™ due to the uncertainty over the potential for government or local authorities policies which could seek to turn people away from diesel â€“ which potentially means that they are holding on to older, more polluting models for longer.
Commenting on the figures, Mike Hawes, SMMT chief executive, said: â€œThe ongoing and substantial decline in new diesel car registrations is concerning, particularly since the evidence indicates consumers and businesses are not switching into alternative technologies, but keeping their older cars running.
â€œGiven fleet renewal is the fastest way to improve air quality and reduce CO2, we need government policy to encourage take up of the latest advanced low emission diesels as, for many drivers, they remain the right choice economically and environmentally.â€