Just the British mile.

Which, bless them, they defined as being 8 furlongs long. Yeah, what the heck is a furlong… you need to be a British horsey type to be familiar with such things. For the rest of us, a furlong is 660 feet. So that makes a mile 8 x 660 = 5280 feet.

In the early hours of this morning I had an embarrassing “light bulb” moment. As previously shown, a foot is simply ⅕ of a Grand Metre ( 1 + π/6). This morning, the flip side of that hit me … that the Grand Metre (especially in the slightly rounded for practical purposes form of 1.524m) is exactly five feet. I suppose we could call that a fiveet.

As a unit of length, it’s not bad, probably more useful than a yard. The problem with the yard is that you need to go through 10 of them before you get back to round numbers, while with the fiveet, every second one is a nice round number and multiple of ten as well. Rather practical.

So from this, we can see that there are exactly 5280/5 = 1056 Grand Metres in a modern British mile.

Q.E.D.