Taconicus wrote on 6 January:

"I sing the music because I love it, and I sing it the way I love to sing it. And if you don't like it, you don't have to listen."

Agree entirely. Perhaps after that, as Hamlet says, "The rest is silence…"

Or perhaps that line suggests another way of considering this issue?

I've heard quite a number of American actors taking on Shakespearean roles. Many of them have (IMHO) performed very creditably, delivering their words with intelligence, with feeling, and with sensitivity to the dynamics of native English speech. Orson Welles' Falstaff, Marlon Brando's Mark Antony, and Paul Robeson's Othello were outstanding examples.   Nevertheless, it was still obvious from their accents that they were Americans.

And yet I wouldn't dream of dismissing what they did as 'mid-Atlantic'. These actors were, I think, trying to preserve the English speech-rhythms of the text, but without faking an English accent. Now there are many British singers who love American folk (and jazz, and rock) music just as much as these American actors love Shakespeare. And the songs they love to sing have speech-rhythms that are just as distinctive as Shakespeare's. To sing them convincingly, it's essential to understand and respect those rhythms. But IMHO it isn't necessary (or even desirable) to produce a perfect facsimile of the original accent.

I would submit that the Beatles sang Carl Perkins songs for exactly the same reason that Orson Welles played Shakespearean roles – because they found them irresistible. And critics who ignore the power and passion of their performances, and merely carp about the 'inauthenticity' of their accents, are totally missing the point.

Wassail!