Thanks to the new system, if you sell your car before its road tax period runs out, you are entitled to a refund for any full months of tax remaining.
How to get your road tax refunded
Once we have informed the DVLA that you no longer own the car, your vehicle tax will be cancelled and if you pay by direct debit this will also be cancelled. You’ll automatically get a refund cheque for any full months left on your vehicle tax. The refund is calculated from the date DVLA gets your information. The cheque is sent to the name and address on the vehicle log book.
Read more about vehicle tax refund on the government site.
Selling an untaxed car to We Want Any Car
It is also possible to sell a car to We Want Any Car without road tax.