On my reading, the majority of posters here seem to think it's OK to exceed the limit by 5 to 10 per cent. Is this because they are all above average drivers with super-fast reaction times, who only drive when surrounded by equally competent drivers?
Or do they all have lifestyles so hectic that time and space must be bent to their schedule?
For myself, I tend to drive at around 65mph on motorways (as that's as fast as my 24-year-old Land Rover will comfortably travel) and around 45-50mph on unrestricted single carriageways. I know how long it takes me to get from A to B and if I have to be at B at a particular time I'll leave earlier.
And arguments about the superior engineering of modern vehicles are specious - the laws of physics remain the same, as does the human capacity for lapses of concentration and stupidity. The sort of person who drives above the limit because s/he lives life in an admin vortex and is perpetually running to catch up is just the sort of disorganised idiot who will either have a crash or (more tragically) cause one.