I guess one of the real problems with the UK not fully committing to the metric system is everyday life.
My generation were taught the intricacies of the "Imperial" system, and the complex calculations needed to determine the weight of water in a cylinder, and the relationship between work and force in foot-lbs and poundals, and BTUs.
Then in secondary school we were introduced to the CGS and MKS systems - the SI system was adopted in many large industries, and especially in science from around the mid 1960s. I worked for over 20 years in laboratories in various industries and from around 1969 onwards never used anything but metric measurements.
I suspect the reason that people still think in terms of pounds, ounces, gallons, yards, rods, poles, perches and stones, amongst many others - has been the lack of education from political circles.
Someone else - more than one - has already commented about the "special relationship" with the USA, and its obsession with Imperial ,measures - they actually still use BTUs in thermodynamic calculations, and have even corrupted the standard imperial pint/gallon and fluid ounce.
The metric, or SI system is simple and very, very effective - the UK still has a long way to go to catch up in public.
But reverting to Imperial concoctions will never happen - it is too costly, and just a jingoistic flag waving exercise - surely??