Re: 100M£ John Brown
"Maybe not pedestrians, but cyclists under and overtaking all the cars sticking to posted 20mph limits maybe need to get a clue that the law applies to them too."
Actually in that particular case it doesn't. Speed limits apply specifically to motor vehicles only, there are no speed limits for cyclists, pedestrians, horses or horse-drawn vehicles.
That's a different issue from whether riding too fast is a good idea or not, but legally there's no obligation to keep to a speed limit.