Actually, "doon" was a poor choice to represent the sound I was going for there. "Dun" might have been better. As for my accent, I pronounce "doon" as "dune." "Ma'am" comes off with same vowel sound as "quack" or "lack" or "back."
dune and June are pronounced the same in my accent. And tube is pronounced "choob". In RP (posh) British English, tube is pronounce "tyoob"
This comment got me to pondering American accents, or more specifically, bemoaning the dwindling number thereof. While you'll occasionally still hear a voice you can place to within a hundred miles of its point of birth, anymore, we're all starting to sound the same. Mainly because our professional class has adopted a mode of speaking that, for lack of a better description, suffers from a deplorable excess of enunciation.
The same thing's happening in Britain to some extent. Not so much with regional accents, but with social class accents. Accent is very tied up with social class and class prejudice over here, i.e. regional accents are working class, then there's a middle class accent and an upper class accent. Both of the latter sound "posh" to me, but I can hear the difference between middle class posh and full-on plummy upper class posh.
There are negative stereotypes associated with all the regional/working-class accents which go above and beyond just negative stereotypes about working class people. And there's also inverted snobbery/reverse class prejudice and stereotypes surrounding the "posh" accents.
These days though, some young middle and upper class people are either naturally picking up or deliberately emulating working class accents, so they blend in more. Because a posh accent among working class people makes you stand out and not generally in a good way. It's also advertising their class privilege, which doesn't generally go in their favour among working class people.
Here's the thing - Prince William and Prince Harry speak with Estuary accents. That's the same accent as me. (I probably still sound much more common than them because Estuary's more of a spectrum than a specific accent, i.e. blending London with the surrounding regional accents, but it's basically the same accent. The name comes for "Thames Estuary" i.e. the spectrum of accents as you go along the Thames Estuary out of London.) That is unheard of in centuries of British history. Class prejudice via accent has been very ingrained into our culture so the idea of Royal princes speaking the same way as me, a commoner whose family origin is the slums of London is just as radical as Prince William marrying a commoner.
We're a long way of actually being free from class prejudice, but seem to be moving in the right direction, so this blending of accents to me is a good thing.
There's some evidence that regional accents are becoming more similar because of TV, but people's accents are tied up with their identity so I think regions will maintain their distinct accents, even if the accents themselves change over time.