According to sales figures from Debenhams, those in the North, Midlands and Ireland tend to buy the bigger sizes, while women in the South and Scotland are a little less busty.
Wales, however, wins the biggest average bra award, with an E-cup being the bestselling size in its stores there.
Nearly four in five women questioned in the Debenhams survey said that they had squeezed into a bra that was too small for them.
The chain's head of lingerie buying and design, Sharon Webb, said there had definitely been a change.
"Sales suggest that breasts are bigger than ever before," the Daily Mail quoted her as saying.
However, those that aren't are certainly getting a little help.
Padded and push-up bras made up 70 per cent of bra sales in Debenhams stores this year, compared with 36 percent in 2010, suggesting that that women are keen to make the most of their figures.
"Confidence is changing the shape of the nation," Webb said.
Webb suggested that curvaceous women like Nigella Lawson, Dita von Teese and Beyonce were making other women feel more confident about their own fuller figures.
"Fit is of paramount importance," she said.
"A great-fitting bra makes you look incredible on the outside and feel fabulous on the inside," Webb added.