THE Mayans predicted that our civilisation would fall in 2012 and, boy, they were right.

We might as well shut up shop now – no point waiting until December 21. The last bastion of human dignity has crumbled.

Predictably, the decline began in the world of celebrity, championed by Kate Moss, Cheryl Cole and the curly-haired chap from One Direction, but has since filtered down to the masses.

I am talking about the adult romper suit, aka The Onesie. Granted, the fashion for all-in-one pyjamas has been around for a while now, but in recent weeks things have taken an unsettling turn. Onesies are now usurping velour tracksuits as the loungewear of choice, be it for popping to yoga class or pottering round B&Q.

When I first wrote about onesies two years ago, I laid down some non-negotiable ground rules. Rule number one: thou shalt not be seen in public wearing it. It's a strictly behind-closed-doors item. Case in point? The other week I was settling down to some Saturday evening television when the doorbell rang. It was the police with an update on my husband's stolen bike.

We chatted for a good 10 minutes, all the while deftly ignoring the elephant in the room: that I was wearing a fleecy red-and-white onesie, looking like an overgrown toddler left home alone. Thinking about it still makes me blush.

But with Debenhams reporting a 155% rise in sales and John Lewis a 73% spike, it's a fad that shows few signs of abating. Which is why I'm setting up The Ministry of Appropriate Onesie Behaviour. First item of business: lobbying for a ban on public wearing. We have endured puffa jackets and Ugg boots, but it's time to draw the line. Who's with me?