PLASTIC bags, what a lot there are in the world - more bags than people, according to the finest guesswork this column can lay its hands on.

The calculation goes something like this: if one person going into a supermarket can come away with, say, 20 bags of shopping, then these bags must out-number people by about 20 to one, especially if the supermarket packs for you, when there is a superabundance of unwanted bags.

These indestructible plastic bags are the spawn of the devil in our house and the undoubted cause of at least half of the world's problems, all the way from our leaking washing machine to hurricane Katrina.

I should like to be able to claim the moral high ground here because we all need to feel moral about something or other, but sadly I can't. My wife is the eco-warrior on this one.

She is becoming a touch obsessed about plastic bags, which is fine by me - until I want one of the things for something or other, only to discover we haven't got any.

It's all very well trying to be green, but if all the plastic bags in the house have disappeared, what do you use to carry empty bottles to the bottle bank? Some of us have been drinking our way through all those bottles of beer and wine just so we can do our bit for recycling, only to find that there's nothing to put them in.

Strictly speaking, this isn't true, but if a columnist can't flex the facts in his own house, then when can he?

We do have bags, made of Hessian, canvas or other longer-lasting materials, to supplement the disappearing carrier bags. We go armed to the supermarket with these so that we can say "a pox on your vile plastic bags" to the checkout person, only we don't because that would be rude and we're not brave or disagreeable enough, and it's not their fault the shopping comes in bags which will still be screwing up the environment in ten years/100 years/1,000 years (delete according to crossness on this issue).

So we say, no thank you, we've got our own. Or my wife does, while I firmly back her up by looking mildly embarrassed and staring off into the distance.

There are so many environmental issues to worry about it's hard to know where to start. Most of us take a pick-and-mix approach, being good about some things and not bothering on others.

I recycle newspapers and bottles, but not tin cans (our recycling box keeps being recycled/nicked by someone or other).

Coffee is another one - I buy fair trade, on the assumption this is doing good somewhere or other in the world. Hopefully it is, but maybe I'm kidding myself, salving my conscience for a penny or two more per cup, or whatever. But I'll keep doing it because it feels right.

As for plastic bags, they are big news all over the world. Just last month, the Indian state of Maharashtra banned the manufacture, sale and use of all plastic bags. The state's leading elected official blamed plastic bags for blocking sewage and drainage systems during the monsoons.

Ireland got there first, not with a ban but a tax. The 15 per cent levy was introduced in March 2002 and was praised by environmental groups around the world, and could now be copied elsewhere.

Yet a report last weekend in The Sunday Times - Ireland found evidence that not all Irish stores bother to add the levy on to the bill. Local councils find it costly and time-consuming to prosecute such staying stores, so a good environmental measure risks being undermined.

According to the Dublin-based newspaper, there are "about a trillion plastic bags used worldwide each year", which is a trillion too many, even though I'm hazy on the mathematics of what constitutes a trillion plastic bags (or a trillion anything).

Incidentally, in Ireland, before the ban, plastic bags were a litter scourge and became known as witches' knickers, "because they frequently appeared up trees, marring rural settings".

So how's that for a slogan? My wife bans witches' knickers...

Updated: 09:02 Thursday, September 08, 2005