Which means UTC is the basis for all nav/atc systems we use.
And before you gentlemen start bashing the french,would you care to remember that one Mrs Thatcher of yours decided to do away with the clock at Greenwhich for -I'm sure-very important costs reasons,and as far as I know,every country in the world has approved the international system of measures which was defined with the participation of a lot of scientists
Lastly,for the few die-hard british system fanatics around,the foot,the pound...etc are defined as fractions of the appropriate metric unit.
In aviation,we keep the nautical mile as the most relevant unit,using a sexagesimal division of time and angles,and the foot as more useful for altitude,but the day they will have accurate enough alt measurement (I will be long retired by then)and they could separate aircraft by 300 ft,meter will be the better unit.
Cheers;