Diesel dropped to around a third of new car registrations in the UK in January, even taking second place even among fleets, despite a much slower rate of decline, according to the latest SMMT data.

Fleets aren’t deserting diesel as quickly as private buyers.

Car registration data for January shows the market as a whole declined 10,949 units (-6.3%) year-on-year, though most of that was down to a weaker retail market, down 7,298 units (9.5%).

Fleet registrations fared better, at 89,513 units (-1.8%) while business registrations dropped to 4,686 units (-29.7%). Overall, fleet and business registrations accounted for 54.7% and 2.9% respectively of the total market, compared to 52.2% and 3.8% in January 2017.

Forthcoming changes to company car tax and vehicle excise duty for diesels, due in April, are not causing a rush for registrations, as appeared to happen before VED reforms last year. Diesel volumes overall were down 25.6% year-on-year in January, taking 35.9% of the total (58,703 units) compared to 45.2% (78,905 units) in 2017.

However, fleets appear to be taking a more cautious approach. Diesel accounted for 45.7% of fleet registrations in January, slightly behind petrol at 48.5% but almost double its share of the private market where only around a quarter of new cars had a diesel engine.

The results come as some within the industry have accused the government of creating a CO2 problem and potentially driving up fleet running costs by appearing to demonise diesel engines. Others have suggested that it’s over-incentivising a move into plug-in hybrids, which real-world data has shown can be less efficient than a petrol engine if they are deployed incorrectly.