Why do British accents disappear when they sing?

Question:

Why do British accents disappear when they sing?

Best Answer - Chosen by Asker: Rick Johnson answered this question with... I think most British people tend to sound more American because historically America has been the root of practically all post-war music, Blues, Soul, Rock and Roll, Funk, Modern Folk, Disco, Rock, Hip Hop and Rap. They have developed along the way with a certain amount of to-ing and fro-ing across the Atlantic, although this seems to have almost come to a standstill as far as chart music recently goes.

The exceptions to the rule are few and far between, but very memorable:

Damian's neighbours- The Proclaimers (Scottish)
The Cranberries (Irish)
Sophie Ellis-Bextor (Southern English)

More often than not modern music is non-rhotic. gangsta rap, cudda, shudda, wudda, ...

Some English people sing with very rhotic accents, you might want to listen to The Wurzels "Oiv go' a bran' new comboined 'arvesterrrrrrr"!!!!!!