The legal requirement in the U.K. is that all vehicles should display a current valid tax disc in a vehicle windscreen and that is should be clearly visible. It is illegal to park your vehicle on the public highway or drive it on a public road without displaying a tax disc. In order to prevent the tax disc falling off the windscreen the best method of ensuring that it stays in position is to place it into either a circular tax disc holder or a shield shape tax disc holder. The advantage of this is that conventionally manufactured tax disc holders of this nature are made with a strong self adhesive backing and as such the tax disc holder will not fall from the windscreen. The tax disc holder should be fixed on the passenger side of the vehicle preferably in the left hand corner of the windscreen. It is best to position the tax disc holder a little way up from the car dashboard so as to ensure that the tax disc is clearly visible in the tax disc holder. In addition to this the tax disc inserted into the tax disc holder should be valid on the particular day it is viewed. It is acceptable to purchase a new tax disc in advance but it should not be displayed in the tax disc holder until the date at which it commences.
The positioning of the tax disc holder is not entirely rigid. The only legal stipulation is that it should not obscure in any way the driver’s view of the road.