From 1 October 2014, the paper tax disc can no longer be displayed on a vehicle windscreen.
If you have a tax disc with any months left to run after this date, then it should be removed from the vehicle windscreen and destroyed.
When purchasing a second hand vehicle, the vehicle tax can no longer be transferred with it and you will need to get new vehicle tax before you can use your vehicle. You can tax the vehicle using the New Keeper Supplement (V5C/2) part of the vehicle registration certificate.
When selling a vehicle after 1 October, you must notify DVLA. Once you have done this you will automatically get a refund for any full calendar months left on the vehicle tax. You will no longer need to make a separate application for a refund of vehicle tax. The DVLA will automatically issue a refund when the notification is received from the person named on the DVLA vehicle register that the vehicle has been sold or transferred. This applies to all types of vehicles including those that are exempt from payment of vehicle tax.