It was in 2002 that an all party Parliamentary Select Committee, after taking opinion from all sides, some saying speed limits should be lower, some higher, reported ‘speed limits are in a mess’.

In 2006 following years of consultation and pilot schemes the Department for Transport circulated its ‘DfT 2006/01 Guidance for Setting Local Speed Limits’

This is a framework for consistent speed limit setting across the UK taking into account all manner of local issues.
It only describes Local Speed Limits so does not discuss overall national speed limits (NSL) determined by road type and vehicle class.