Two sides to the MOT. The first, it representing an affirmation that a vehicle was roadworthy on a particular date, isn't relevant to us here.
The second is its function as a document for which a vehicle must have one "on date". The piece of paper that forms your MOT still exists, it's still in your desk drawer, it hasn't gone anywhere, but it can not lawfully be used to allow the vehicle to be driven or re taxed until the motor in question has been inspected. Therefore the privileges the MOT certificate bestows are effectively suspended, unusable, meaningless, until the PN process is completed. During that period it becomes a piece of paper with no legal use.
Once the process is complete the certificate allows you tax the car, or it's virtual existence is used to tax the car in line.
If a constable in uniform stops you at the roadside and asks to see the MOT you commit an offence then and there if you fail to produce it (although the HORT1 process allows prosecution to be held in abeyance for 7 days to give you the opportunity to produce it a police station).
So, the MOT certificate has its uses, and regardless of what it represents (or not) re a vehicles roadworthyness you simply must have one on a 3+ year old car.
So, iwt's essential in order to lawfully use a car - sounds pretty useful to me!
So, the PN declares the vehicle un roadworthy despite the existence of an otherwise valid MOT and that MOT then ceases to be an instrument by which you can acquire your vehicle licence. So, seeing as a PN suspends the lawful uses of the MOT, perhaps you can explain how it had no effect? You issue my a PN and until the process is completed my MOT is of no use whatsoever as a legal document. Once the process is complete I can then use it as a document to lawfully use my vehicle or buy my tax.
Let us do a little thought experiment;
Ive issued you a PN because you've been naughty and you've got defective brakes on your Lamborghini (may as well have you driving a flash car in the name of science!). You've had it towed to Bombsite Motors who advise they are going to have to wait a week for the parts. Oh dear.
During this time you can not use the MOT to re tax the car.
Even if you sneakily kidnapped your car back one night the MOT document would not be accepted as valid by a bobby because PNC would show a PN in force.
So what can that MOT certificate lawfully be used for during this time?