That is because there is no official English.

At least the UN considers the British spelling as the official one:

> https://en.wikipedia.org/wiki/Official_languages_of_the_Unit...

But for a tiny, well connected island Britain has a remarkable diversity in pronunciation.

Even speakers of "RP", a supposedly region-neutral "educated" accent which is as close to "official" British English as we've ever had permits variations in pronunciation so marked that speakers of one variant can find speakers of other variants' pronunciation of a particular word comical.

British spelling is not the British accent. One estimate had the English accent changing about every 25 miles as you travel through Britain.

Have you seen Hot Fuzz? In it, the police visit a farmer with a strong West Country accent, and take an interpreter with them. All parties are speaking English in the scene, but the farmer's words are so strongly accented, the interpreter has to translate. That scene was based on a direct observation that the writers made while researching the film...

I would expect that to have gone away to some degree with the rise of movies, radio, and television. Certainly it did in the United States. We still do have regional accents, of course, but I remember seeing a farmer from Appalachia on television getting subtitles when I was a kid. I doubt that ever happens today.

Still happens in the Netherlands, which is of course far smaller still. People switch from their local dialect to standard Dutch on TV, but still have accents that confuse city people or those living on the other side of the country.

I sometimes see American TV stations subtitle American-dialect speakers. Mostly this is due to audio quality, but it happens frequently enough with urban speakers of African American Vernacular English.

Standard English on television probably certainly helps speakers of less-prestigious lects understand Standard English, but not necessarily inspires them to produce it.

Oh, stewardess. I speak Jive.

https://www.youtube.com/watch?v=g0j2dVuhr6s

The UN also says North Korea isn't allowed to have nukes. Look how well that turned out...

The UN has no real authority on anything.