Sorry, beg to differ. DVA state that you can only drive a car that is insured, but has no MOT or tax, to and from an MOT Centre (pre Booked Test) or to a VOSA/DVA inspection centre (say for registering or reclassifying) So if a car fails MOT as long as it is going back to your home, OR a place for repair, it can be driven on road without MOT or Tax, Must be insured, also MOT centre are required, if failure considered dangerous, to impound vehicle/prevent it being moved until you get a transporter to move it. That's from 2 MOT inspectors directly, and the DVA website.
If the failure is dangerous, and you insist on moving it, they would contact the police.
That's MOT centres in NI, which are government owned and run. But the website is for all localities.