I will go through this section by section later but I want to make sure that the driver fault and serious/dangerous is explained thoroughly.
I've highlighted with the green arrow the "cutting corners" part of 21 - Junctions and it can be seen that this (along with all others in this part) can be scored as driver fault, serious or dangerous. Most people will know that when turning right, you are meant to stay on your side of the road and not "cut the corner. Looking at the picture below, you turn roughly following the green arrow and keep off the "Turn after me" patch.
It would be a generally be a driver fault (minor) as long as there isn't a vehicle approaching following the green arrow. If that vehicle had to slow down it would be a serious (major) fault; if you hit the car it would be a dangerous fault.
A single serious or dangerous fault will, of course, cause a test failure.
Notice that I have given this form 2 driver faults for cutting corners. Another way to fail a driving test is multiples of the same fault. You would get away with 2 but not 5 in one category, the easiest way is to drive properly and get none.
These same principles can be applied to most faults in a driving test. So let's have a look at the other categories in this list.
13. Move Off: You will be asked to do this several times in your test. You can make mistakes in safety and/or control. Safety will generally mean that you didn't take effective observation ahead, behind and into the blind spot (also behind you). Again these could be driver faults or serious depending on the situation - don't make another road user take evasive action (mostly making them slow).
Stalling an engine in this situation will generally be a driver fault for poor control, it is hard to imagine how this could be a serious fault, since you are already stationary. But I suppose that multiple stalls would be a fairly common fail, especially for a very nervous driver.
14. Use of Mirrors: this is a very common area of failure, especially use of mirrors before change of direction. In fact during test in 2011 there were 130624 candidates who failed in this category. This is an area where examiner's are very critical (quite rightly). An good example would be when turning right at most roundabout, at some point you need to change lanes (right to left) and you need to ensure that the left lane is clear. I will cover roundabouts in a later post as they are the most hazardous junction to negotiate. Use of mirrors before change of speed often happens when the driver is asked to stop on the left but doesn't check that there is a vehicle behind.