Registrations of diesel cars in the UK were down by 30.6% in November, when the overall market declined for the eighth consecutive month.
In total, 163,541 new cars were registered last month, 11.2% less than in November 2016.
Sales of petrol cars grew 5% to 92,944 units, giving petrol a 56.8% market share – up from 48.1% at the same point last year.
This was accompanied by 33.1% growth in alternatively fuelled vehicle registrations, bringing their market share up to 5.4%. However, these could not counter the 27,163 unit drop in diesels, resulting in a decline in the overall market.
Private registrations were actually down by the smallest percentage, falling 5.1% in November. Business and fleet registrations fell by 33.6% and 14.1% respectively, with the impact of these sectors (which represent a respective 52% and 2.7% of the market) key contributions to last month's shrinking numbers.
So far in 2017, 2,388,144 new cars have been registered for Britain's roads – a 5% drop, or 126,620 cars, on the same period last year.
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Society of Motor Manufacturers and Traders chief executive Mike Hawes said: "An eighth month of decline in the new car market is a major concern, with falling business and consumer confidence exacerbated by ongoing anti-diesel messages from the Government.
"Diesel remains the right choice for many drivers, not least because of its fuel economy and lower CO2 emissions. The decision to tax the latest low-emission diesels is a step backwards and will only discourage drivers from trading in their older, more polluting cars."
Hawes explained that the decrease in fleet registrations will have a marked impact on the UK's air quality improvements, with "detrimental environmental and economic consequences" if the market continues to shift away from the newest, cleanest diesels.
Last month, the Government introduced diesel tax hikes that affected both private and fleet buyers. With new legislation announced in the autumn budget, all new diesel vehicles that do not conform to Real Driving Emissions step 2 test standards are subject to an increase in tax.
The step 2 standard doesn't come into force until 2020, meaning no new models can be graded at that level. The industry has therefore hit back, claiming that the new standards demonise the latest, cleanest diesels, even though some tests (including Autocar's own) show that they can be cleaner than the equivalent petrol models.
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