The Big Question: What more can Britain do to beat its addiction to plastic bags?

Why are we asking this now?

Because yesterday the Government's anti-waste body, Wrap, announced that plastic bag use in the UK had dropped from 13.4 billion in 2007 to 9.9 billion in 2008 – a reduction of 26 per cent, or 3.5 billion bags.

That's a pretty hefty reduction in just 12 months, isn't it?

Yes, indeed it is; the 3.5 billion bags which have been cut from use, laid end to end, would stretch to the Moon and back twice, or around the Earth 44 times, Wrap obligingly points out (which is a bizarre but undeniably impressive image). On the other hand, we are still using 10 billion bags a year – approximately 166 bags for every man, woman, child and infant in these islands. That's hardly a kicked habit.

So how many of those 10 billion can we cut?

There's the rub. In December, seven of the major supermarkets, which are the leading plastic bag sources, agreed that they would seek a 50 per cent reduction in single-use bags by May this year, as against May 2006. It is not clear yet how they are doing, but the rate of change indicated in the UK figures released yesterday certainly suggest that the target is achievable. But where do we go from there? In December, the Government hinted at a 70 per cent eventual reduction in UK plastic bag use (in Whitehall-speak, this is an "aspiration" rather than a target. Targets you have to meet. Aspirations, you aspire to). Could that be attained? Even if it could, we would still be using four billion bags a year. That's a long way from zero.

Why does all this matter?

Because plastic bags are one of the greatest scourges of the consumer society – or to be more precise, of the throwaway society. First introduced in the US in 1957, and into the rest of the world by the late 1960s, they have been found so convenient that they have come to be used in mind-boggling numbers: in the world as a whole, the annual total manufactured now probably exceeds a trillion – that is, one million billion, or 1,000,000,000,000,000. And according to the British Antarctic Survey, plastic bags have gone from being rare in the late Eighties and early Nineties to being found almost everywhere across the planet, from Spitsbergen, at latitude 78 degrees North, to the Falkland Islands at 51 degrees South. They are among the 12 items of debris most often found in coastal clean-ups. On land they are ubiquitous too. Windblown plastic bags are so prevalent in Africa that a cottage industry has sprung up harvesting bags and using them to weave hats, and even bags, with one group harvesting 30,000 per month. In some developing countries they are a major nuisance in blocking sewage systems.

What matters is what happens to them after use. Enormous numbers end up in landfill or incinerators, itself an enormous waste of the petrochemical products which have gone into their manufacture; but billions get into the environment, especially the marine environment, where their lack of rapid degradability makes them a persistent and terrible threat to marine life.

What threat do degrading bags present to nature?

Sea turtles mistake them for their jellyfish food and choke on them; albatrosses mistake them for squid and die a similar death; dolphins have been found dead with plastic bags blocking their blowholes. The British wildlife film-maker Rebecca Hosking was staggered by the plastic-bag-induced mortality of Laysan albatrosses on the Pacific island of Midway; she found that two-fifths of the 500,000 Laysan chicks born each year die, the vast majority from ingesting plastic that their parents have mistakenly brought back as food. As a result, Ms Hosking started a movement to turn her home town of Modbury into Britain's first plastic bag-free community, which many residents and retailers have enthusiastically joined.

So is a plastic bag-free Britain possible?

Perhaps. Who could have imagined half-a-century ago that Britain's public places would one day all become cigarette smoke-free? Of that we would all be using lead-free petrol? Who would have thought even a decade ago, come to that, that about two-thirds of us would by now be actively engaged in recycling? Major shifts in public behaviour can certainly occur.

So what would be needed to make such a change?

Above all, a general change in consumer attitudes, towards the "re-use habit" – employing reusable shopping bags. Older people will remember how this was entirely the norm before the late 1960s; households, and in particular, housewives – as they then were – had a "shopping bag", a sturdy receptacle which was used to carry items bought in the daily shopping expedition. But that was the very different pattern of household shopping then – the purchase of a much smaller number of items, on a daily basis, after a walk to small shops – which were local. Today the housewife is largely a vanished species, and many of us tend to drive to the supermarket once a week and fill up the boot with seven days' worth of provisions, for which plastic bags, of course, are fantastically useful. It's a hard habit to break.

Why have we seen such a dramatic drop in plastic bag use this year?

Because the leading supermarkets and other retailers are making a major effort to wean us from the habit, with a whole host of initiatives, ranging from "bags for life" schemes to bag-free checkouts. It is clear that habits are starting to change; reusable bags are more visible than they were even two years ago. Wrap's Dr Richard Swannell said yesterday: "When you go into supermarkets or go down the High Street, there is a real plethora of people with reusable bags."

Should the Government be putting a tax on plastic bags?

The Government is considering the idea, and Gordon Brown has said that if actions by the retailers do not achieve the desired result, then direct intervention is a possibility. What people have in mind is the example of Ireland, where in 2002 a levy of €0.22 – the PlasTax – was introduced on all plastic bags, the first of its kind in the world. This quickly prompted a quite astonishing reduction of 90 per cent, from 1.2 billion bags a year to fewer than 200,000, and an enormous uptake in the use of cloth bags – with the revenue from the tax ring-fenced for environmental clean-up schemes.

What is the Government going to do next?

In the Climate Change Act, which was introduced late last year, the Government gave itself the power to bring in a plastic bag levy. You might well think that it wouldn't give itself a power it wasn't eventually going to use. Certainly, kicking the habit completely may well require stronger action. To get a sense of the scale of the problem, check out the website Reusablebags.com, which has a "clock" showing how many plastic bags have been produced so far in 2009. At 6pm last night, the figure was 76.37 billion.

Will Britain soon be a plastic bag-free nation?

Yes...

* The trend in plastic bag use is definitely falling, which suggests we are moving in the right direction

* The Government intends to drive bag use down even further

* Ministers may bring in a tax, which in Ireland has reduced usage by 94 per cent, which will help further

No...

* We are now too attached to the weekly supermarket shop, which plastic bags facilitate

* It is unrealistic to expect everyone to return to the habits of the 1960s

* Plastic bags are simply too convenient for people to give up altogether, and they certainly hold heavy shopping better than paper ones