How You Can Fail Test By Driving Too Slowly

We all know driving over the speed limit is a no-no on the test (as well as before and after), but did you know driving too slowly can be a serious fault, and can lead to a fail?
This fault will come under inappropriate speed.
Yes too fast is obvious, and while you may be deemed to be driving too fast and at the same time be well within the speed limit for the road conditions, too slow can be just as much an issue to other drivers.
Examiners want to see a confident drive, and driving too slow on a clear, dry road with plenty of room and visibility is evidence of a nervous driver lacking in confidence.
I have a colleague whose candidate received two serious faults, [...]