Miniskirts, hot pants and belly button piercings should also be avoided after mid-thirties. And it's not just crop tops and bikinis that the over-30s need to avoid, with the miniskirt being labeled as "too old" for those aged 37 or above, even hot pants should be ditched at 35.

Ruth Gresty, spokeswoman for the All-Bran Five Day Challenge, said, "People may say, 'If you've got it, flaunt it,' but it seems that this isn't always the case for some of our wardrobe staples."

The study conducted on 2,000 women also found that leggings should be avoided after one reaches 37 years of age and stilettos are a complete no-no if you are 41-plus. Belly button piercings should be removed by the time you turn 35, while long hair should be given a chop at 42 for a shorter, more "mature" look.

As many as 27 percent believed that ladies should stop shopping in younger clothes stores like Topshop and Miss Selfridge once they reach their early forties. Over a fifth of those polled said they would put age aside and show off their body if they had a flatter or less bloated looking tummy like celebrities, but admitted they found it incredibly hard to achieve. Another 16 percent believe in the mantra, "if you've got it, flaunt it".

Researchers also found that women are taking the lead from celebrities, with 67 percent of those surveyed said that famous females are making it more acceptable for women to wear belly-bearing clothes after a certain age.