I noticed that Potterverse uses the imperial system of measurement: 10 inches of parchment for a Transfiguration essay; Harry fell 50 feet from his broom; the dragon flew for miles it seemed; Hermione's rucksack weighed 35 pounds. Etc.
I researched both the imperial and metric systems and I know that the UK uses both the metric system and the imperial system, but I don't know how equally. Every time the subject has come up when I've been talking with someone from the UK or one of the European countries, that person has been staunchly pro-metric system.
Why did J.K. Rowling choose the imperial system for Potterverse?
Edited to Add: I'm looking for a quote -- verbal or written -- from J.K. Rowling or a reference from canon. I'm not asking this as a speculative question.