The overall vehicle market is down 4.6 per cent in the year to date, with 2.22m cars registered in the first 10 months of 2017.
However, despite coming under some pressure, the SMMT data suggests that petrol and diesel cars still dominate the market for new vehicles, with a total of 946,537 diesel and 1,175,697 petrol cars registered for sale in the United Kingdom, and 102,369 alternatively fuelled vehicles throughout 2017.
Demand from business and fleet buyers fell 26.8pc and 13pc respectively, while registrations among private vehicle buyers dropped 10.1 per cent.
Year to date registrations decrease -4.6%.
He said consumers needed "urgent reassurance" that the latest, low emission diesel cars would not face any bans, charges or restrictions.
Alternatively-fuelled vehicles are up nearly 37 per cent since October 2016, wth petrol cars increasing by a smaller 2.7 per cent.
Confidence and trust of diesel cars has plummeted since the 2015 "diesel gate" scandal which revealed the true emissions output of these cars.
The SMMT said falling confidence among buyers continued to impact the market with business and fleet demand down -26.8% and -13% respectively.
Overall new vehicle registrations declined to 158,192, a fall of 12.2 per cent compared to the same time previous year, and sales of diesel engined auto fell even more dramatically - by a whopping 29.9 per cent.
The Government said earlier this year it would aim to end sales of conventional diesel and petrol cars by 2040, while ministers are said to be drawing up plans to tax diesel cars more heavily in towns and increase duty on the fuel. Meanwhile, dealers reported -10.1% fewer private buyers taking delivery of new cars in the month.
Richard Jones, managing director at Black Horse one of the UK's leading motor finance providers, and part of Lloyds Banking Group, believes the latest data suggests the new auto market is moving to a more sustainable position.
"Looking beyond that the uncertainties still facing the UK economy make it hard to make a robust forecast for 2018 as a whole, however the determinants such as UK GDP and employment levels remain robust".
Demand for diesel vehicles plunged 29.9 per cent in October as a result.
"The pace of take-up of Alternative Fuelled Vehicles (AFVs) is encouraging, but crucial to drivers and fleets seeing the environmental and cost-benefits of AFVs is driver behaviour".