It's a bloody joke really, they have a database the police can check but then say 'if you don't display it's a £200 fine mate'. Why? They seem to make the regs as difficult as possible so they have an excuse to get more cash out of people. Most people get lucky and I think if you were ok with the copper you would have to be unlucky to get done, but if they are down on their luck and need to improve their 'crime detection rate' then who knows.
Obviously the failure to display offence has been around since long before the ability to tax your vehicle on line has. Originally it existed so that the authorities could tell visibly which vehicles were actually taxed, and which were not, as they had no other way of checking at the time. I don't think its that regularly enforced any more, except where a traffic officer chooses to enforce it upon a particular driver to demonstrate a point. These days I think the main point of the offence is to get you to actually display the tax disc in the vehicle, otherwise with the online taxation system people just wouldn't bother taking it out of the envelope when it arrives in the post.There are also tax exempt vehicles such as pre 73 historic vehicles, fire engines, ambulances and certain disabled drivers, all of which are not actually required to pay road tax but are still legally required to display a valid tax disc.
Contrary to popular belief though, it generally costs more in administration costs to bring about a prosecution, than the authorities actually make back out of the fine. So the idea that it's a way of making money out of people really isn't the case.
Edited by AVV IT, 27 September 2012 - 07:37 PM.