The situation is clear. The tester has an obligation to declare a vehicle as dangerous if that indeed is what it is. If this didnt happen in the case of a corroded brake pipe then he is implicitly saying the vehicle is not inherently dangerous, just that it is likely to become so before the next test.
However, follow this little thought experiment ...........if the driver hits the brakes in an emergency stop and a pipe blows, following which (irrespective of brakes as a contributory cause) he hits another vehicle or squishes a pedestrian, what's there to stop the insurer wriggling out of stumping up on the basis that there was a known defect?
It now becomes the responsibilty of the driver to prove that there was no leak immediately prior to the accident and that brake performance was unaffected until after both vehicles came to rest.
I suspect that conversely, there would be a little more room for maneuver in a death by dangereous driving charge, since the prosecution would have to prove that the brake pipe was a significant component of the cause of the crash or the severity of the result. Driver argues that pipe popped after or during the crash so can claim reasonable doubt.
It is NOT necesarily legal to drive an MOT failure to get repairs done even if still in date. For example, if the car has failed for a bald tyre then 3 points are waiting if you get pulled up. An insurer would almost definately back heel a claim as well, it wouldn't even need to be raining. Possession of a valid MOT is no guarantee of roadworthiness, only that the vehicle was okay on the day it passed.
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