I think I have read that legally speaking, for measuring distances on public roads, only miles and yards are "legal tender". A bit of an anomaly in our otherwise largely metricated (UK) world.
My first job was in late 1968, for a firm that made medical equipment. I worked alongside engineers (but only as a lowly lab assistant). "British" units and components sized in those units were still heavily in use, but were gradually being superseded by metric ones. There was a fairly strong drive to metricate industry (and later commerce) at around that time.
There was a nice graphical logo that you used to see (probably promoted by the DTI or whatever it was called then), including what I can only describe as a "lazy M" - I i.e. sort of 3D "M", at 45 degrees, and possibly the rest of the letters of the word "metric" (or "metricate").
I tried to find an example on Google images, but so far without success.
It always seems to me that the metrication process in the UK was never fully completed though.
Edit: This article is quite interesting, and one of the symbols among those graphics looks what I vaguely remember (although there might have been more than one version of it):
Edit2: found a single image version: