I was always taught that the speed limit was a "LIMIT" ..not a "TARGET" ... there are many times, and places, where to be travelling at the speed limit is downright stupid and bloody dangerous.
If someone is of the opinion that the "safe" speed to be driving is 10 miles below the limit, THAT IS THEIR RIGHT, and no-one has any "duty" to drive at the speed "YOU" want to go at.
When I was taught to drive you had to drive at the speed limit where traffic and conditions allowed to show that you were competent, and you got a mark against you on your test if you drove below the speed limit if conditions allowed and my girlfriend past her test around nine years ago and it was exactly the same for her.
I went past a guy last week who was doing 40 in the outside lane of a NSL dual carriageway, the inside lane was clear, weather conditions were good yet he looked terrified, I think he should have been on a bus as driving clearly wasn`t for him. If he had been displaying `P` plates then you can cut him a bit of slack but all he was doing was winding everybody up cos he should have done the right thing and pulled over but no, he just sat in the outside lane oblivious to what he was causing.
A lot of my journey is dual carriageway with a fair chunk of it being NSL and there are so many people hogging the outside lane driving below the speed limit yet refusing to pull over to let people past.
We should drive on the left unless overtaking.
AFAIK there are no roads in the UK that have a statutory "minimum" speed, perhaps there should be, but that is a different matter.
Tyne tunnel is one I believe and there is a road sign for the minimum speed limit