Statistics published today by the U.K. Department for Transport (DfT) show that in 2022 85% of the car drivers in Great Britain broke the law by driving faster than the speed limit in 20mph zones. On roads with a 30mph maximum, 50% of car drivers broke the law, reveals the annual DfT report on speed limit compliance.
The measurements are based on speed data from a sample of Automatic Traffic Counters (ATCs) around the country. These exclude locations where external factors might restrict driver behavior, such as at junctions, on hills, beside sharp bends or where speed cameras are visible, says the DfT report.
My understanding is most 20mph zones are simply advisory, as they don't have traffic orders.
They are not.