If it was her real voice, I'd be fully in support. I don't like to hear British bands singing in cod-American accents (Alabama 3 and The Broken Family Band are excused, because it's all part of the joke for them, but Toploader need shooting), and like to hear natural accents. If she's putting it on, that's not so good - although God knows Damon Albarn has been getting away with his Mockney schtick for years.
Can't dislike a song with the lyrics "now you've got sick on my trainers" though ;-), and would happily have seen it go to number 1 if only to get rid of that boring Rihanna drivel a bit quicker.