Twelve years ago I had a spell in hospital. They were feeding me through a tube and I lost a lot of weight. During a nightshirted shuffle around the ward, accompanied by my drip-feed, the nurses at their station asked me how I was feeling. I expressed concern that my bum seemed to have disappeared. They laughingly professed envy and asked my secret.

At that time, and for many decades prior, it was fashionable for women to want smaller bottoms than the ones nature had endowed them with. It was even a meme before memes became fashionable: “Does my bum look big in this?”

It was not always so, of course. In the mid-Victorian era artificial bottoms in the form of bustles were all the rage.

Now the wheel has come full circle and big bottoms are very definitely in. By way of evidence I present (top right of this post) the cover of an Australian Sunday supplement. But who or what caused this seismic shift? Was it Pippa Middleton’s doing, when her behind stole the show at her sister’s wedding to Prince William? Or was it engineered by the Kardashian clan for some dark purpose?

Can anyone enlighten me? Who decides these things? How is the signal sent to all the women in the world? By what alchemy are people’s self-perceptions turned upside-down overnight?