There have long been 20MPH speed limits in Britain; but they were few and far between, and only used in specific areas such as parks. Each had to be authorized by the secretary of state for transport.
The rot set in when the law was changed to allow councils to set limits themselves. This new power quickly went to their heads.
The worst abuse of this power came in Wales, when the Senedd arrogantly decided to impose 20MPH in all urban areas, despite massive public opposition.
The ABD supports 20MPH limits in some places at some times, such as when children are arriving at, and leaving, school; but imposing them 24 hours a day, 365 days a year across wide areas incites contempt for all speed limits and undermines fundamental road safety principles.
#20isTooSlow (Spoken as Two-Oh not Twenty)