> The British pronounce it as "istory," so they use "an" before.

"The British" aren't monolithic and neither are our approaches to this.

I certainly don't say "it is an historic day" or "staying at an hotel" with the soft H, because to me, in the 21st century, it's an upper class affectation (I am from a middle class background and from the commuter belt 30 miles south of London).

I moved to a slightly posher place and I know people who do say "an historic day" (soft H) still but it's largely out of habit/age/schooling.

The BBC have stopped doing this, as a rule. The monarchy have moderated this aspect of their speech too — I am sure I remember the younger Prince Charles say "an historic day" with the soft H, but I am fairly sure he would now say "a historic day" with the hard H; he has been trying to progressively moderate his RP accent for the last 25 years or so.

ETA: clarification in reply to reply