While the mile will be here to stay for a long time (due, principally, to road signage) there aren't many imperial measurements that are familiar to people today. And why should they be?
I'm not so sure that road signage needs to be a major issue.
Australia managed to switch to kilometres without much of an issue on the roads. People were told what the nearest equivalent speed was, and car dealers fitted printed inserts to speedometers for people who needed them.
Printed inserts would work just as well today as they did over forty years ago for cars with analogue speedos, and cars with digital displays would be even simpler to swap over with it just needing a few minutes' work with a laptop connected.
and I believe one of the Mars probes failed because some of the calculations assumed the wrong units.
I thought that was caused by the contractor paying inadequate attention to the specifications they were to work with, combined with the decline in engineering competency at NASA which peaked during the Apollo program when they had engineers who went through things like that with a fine tooth comb. There would have been plenty of opportunity for the contractor to pick the wrong unit even if the metric system wasn't involved.
Even Britain uses metric most of the time, with the exception of speed on the roads and railways, and Network Rail still uses miles and chains or yards for position measurement on most of the network. The driver's display on the Javelin sets changes from km/h to mph when it leaves HS1!
I believe that when routes are converted to ERTMS the speed measurement will all be in km/h.
I'd be amazed if NR engineering works were not already done completely in metric units, with the imperial units left just for the speeds and distances seen by train drivers and the like. Professional quality works need professional quality measurements and surveys!
Load of crap, This is Britain, we should be using BRITISH weights & measures, never mind all the foreign rubbish. Why should we change? the likes of America don't change. A mile, a foot, an inch and a pound & pence, gallon, pints. loosing out identity.
I think your energy might be better focused upon returning to conventional English spelling than the Imperial system of measurements. The imperial system of measurement was derived from Rome, not Britain, and therefore the metric system is closer (both geographically and culturally) to being a true British system.