Perhaps the UK should adopt a similar policy to other countries. Having driven in parts of France at least once or twice a year for many years, if I recall correctly they have motorway speed limits of 135km/h (around 85mph) in dry conditions , reduced to 110km/h (around 70mph) is wet condition. These are considered a maximum speed and are heavily enforced in many areas with stricter rules and higher fines compared to UK.
Most of us are well aware that if you observe the 70mph speed limit on our motorways you will get overtaken by almost every type of vehicle.