[bashtoni]

The fact that they believe there to be a single 'British' accent means this can be quickly discounted as nonsense.

[tavavex]

When people mention a single "British accent", in 99% of the cases it's just a more widely understood shorthand for Received Pronunciation. I don't see how that's bad or wrong, considering how common it is in education.

[CamouflagedKiwi]

It's not common any more, very few people really speak RP these days. The more usual thing accent that people might think of is sometimes called "Standard Southern British" (I've heard "BBC English" as well).

[noja]

I would say in 99% of cases people mean Estuary English.

[TurkTurkleton]

I mean, if you want to be like that, you could generalize that statement to "the fact that they believe there to be a single `$LANGUAGE_OR_REGION` accent means this can be quickly discounted as nonsense". Other languages, and other varieties of English, have regional variation as well, after all--although in the case of other languages, I'll grant that the accents of, say, two German speakers from different regions might not be as distinct from each other in English as they are in German.

At any rate, I was looking forward to finding out what the accent oracle thought of my native US English accent, which sounds northern to southerners and southern to northerners, but I guess it'd probably just flag it as "American".