the Queen's English accent
Elizabeth has modified her accent quite a lot over the years, partly because it sounded so ridiculous. Very few people speak like the Queen or her dreadful family. As for the dying aristocracy, their incoherent drawl is a little hard on the ears.
It is true that the English spoken and pronounced in the London 'Home Counties', or by educated speakers in the London-Oxford-Cambridge triangle is generally accepted as the prestige accent, but I think people in those areas are more aware nowadays of the richness, diversity and clarity of many other regional accents. Many accents which were seen as comical by southeners twenty years ago are now regularly heard without scorn on BBC radio, etc.
As for teaching English, it's certainly a thorny question as to what accent the teacher should present. Most teachers, as with most university-educated people, have their regional accents at least flattened a bit, partly from being exposed to the prestige accent more than others, and partly, I suspect, because it's an almost inevitable consequence of studying and mixing with people from various backgrounds. I think it only fair that students of English are given a clear model accent to emulate. Whether that is Morningside Edinburgh, Southampton, Galway or Boston (Linc. or Mass.), as long as it's clear, there shouldn't be a problem.
On average, an educated middle class Scot for example speaks better English than their counterpart in England. True.
Very true.
I think Radosław Sikorski's accent sounds very pleasant - Pembroke College, University of Oxford
I think he learned a lot from being a member of the Bullingdon Club!