Re: We're not robots! Highways Agency & Avon and Somerset Police beg to differ.
... must ... resist ... the .... troll ... sorry, I just can't.
"No limit showing, no cameras seen, many would argue that it felt safer sticking to 80mph on an empty motorway,"
I wouldn't. The motorway speed limit is 70mph unless a variable limit is posted. I learned that a long time before I passed my driving test, and that was 25+ years ago. I don't recall if they had the overhead limit signs back then but they certainly had the metal ones around roadworks. It really is very simple. Most of the rest of the post is just the usual "why is the fascist state stopping me from driving fast?" whine.
Also I just googled "M4 71mph speeding fines", expecting a torrent of articles about the torrent of fines. Unsurprisingly there were none. I did find a 2015 discussion board entry where someone asked "not sure if this is a myth but...", and all the responses said "it almost certainly is".
I also found http://www.ukmotorists.com/speeding%20fines2.asp where people appear to be able to post their own conviction details. The lowest I found in a 70mph zone was 78mph - on an dual carriageway, not a motorway - but the majority were well over 85.
And before you ask, no I don't speed. I have done, but when I bought my current car 7 years ago, it had an MPG display and I quickly adjusted my driving to "get the high score". I rarely do more than 60 on motorways now, even on long journeys. Getting 450-500 miles per tank from a 1.4l hatchback is much more satisfying.
Cue the downvotes from the petrolheads...