From the Gov website
"New vehicles with a list price of more than £40,000
If a vehicle has a list price (the published price before any discounts) of more than £40,000, the rate of tax is based on CO2 for the first year.
After the first year, the rate depends on the type of vehicle (petrol, diesel, alternative fuel or zero emissions) and an additional rate of £310 a year for the next 5 years.
After those 5 years, the vehicle will then be taxed at one of the standard rates (£140, £130, or £0, depending on vehicle type)."
https://www.gov.uk/government/news/new-vehicle-tax-rates-from-1-april-2017