Here's the Wikipedia rundown of the characters.
Sue Johnston as Barbara RoylePerhaps someone should tell the BBC then. Chain-smokers both, apparently, they somehow managed to survive an entire politically-incorrect 2010 Christmas without even a hint of the existence of tobacco or sight of an ashtray. Barbara hasn't smoked for two years, and Denise enjoyed just a sneaky one last Christmas in a caravan.
She is often forgetful and a little scatter-brained. She and Denise chain smoke.
Caroline Aherne as Denise Best
Denise is known for pulling right back on a ciggie. Her and Barbara love smoking and often fill the ash tray.
The Beeb seem happy to portray chavs eating shite, dubiously claiming benefits, binge-drinking cheap crap and generally being stupid or borderline criminal, but it would appear that some unapproved behaviour is now simply too shocking to be shown.