But amounts of packaging continue to grow, and environmental organisations are concerned that young people are becoming hardened litter louts.
Are we keeping Britain tidy?
Estimates of how much local authorities spend picking up Britain's litter run to more than pound;450 million every year. While it might seem like a stereotype, young people are unfortunately at the heart of the problem.
Sweet wrappers, cigarette ends and chewing gum top the list, but the fastest growing litter scourge is food wrapping, which proliferates by about 12 per cent a year. Young people are big consumers of fast food, so they have plenty of leftover cartons, bags and cans to drop. In schools alone the clean-up bill is pound;39 million, says Encams, the environmental charity behind Keep Britain Tidy and Eco-Schools.
Another fine mess
It is illegal to drop litter, with a possible punishment of an on-the-spot fine of pound;50. However, until recently cash collected by local authorities from litter culprits belonged to central government and had to be forwarded to Whitehall. "There wasn't much motivation among councils to fund and administer claims against people who littered," says Peter Gibson of Encams. "But the law was changed last year and now the councils get to keep the money. Since then there have been many more fines imposed."
Spurred on by the thought of a bit of extra cash, many cities have launched new litter campaigns. Manchester, for example, has successfully fined perpetrators up to pound;500, with sometimes as much as pound;288 in court costs. The council also has a policy of naming and shaming those prosecuted on its website. CCTV is being used to catch offenders, and some local authorities are introducing environmental wardens who have the power to impose on-the-spot fines and who deal with anti-social behaviour, including littering.
It's not all down to untidy teens: everyone is a potential litter lout.
Encams has found that adults are just as likely as children to discard their fast-food junk and walk away without an ounce of guilt. But because young people are the biggest consumers, they are also the biggest litter bugs. "It's difficult to say exactly who is dropping the litter unless you see it fall from someone's hand, but from the make-up of litter and its placement we are pretty confident the vast majority is coming from teenagers," says Mr Gibson. "When you talk to young people it's hard to find someone who hasn't dropped litter. They seem to feel no guilt about discarding their rubbish on the streets." The charity is currently measuring the amount of litter dropped in areas surrounding schools and later this year hopes to show exactly how much litter children are discarding.
The Youth Litter report, published by Encams last year, found four main types of inveterate litter dropper. Those who were "just not bothered" tended to be girls. For them, litter just happens: walking down the street as they chat or eat, they drop litter without thinking. Peer pressure came into play with the second group, who "don't want to be seen as geeks".
While they were unlikely to litter while on their own, they behaved differently when out with their mates. For boys in particular, dropping litter was simply cool. The third category used litter as a sign of rebelliousness and, again, tended to drop most when with others. Finally, there was the "blame it on the bins" brigade. Although this group knew littering was wrong, they found plenty of excuses not to clear up and needed bins to be under their noses before they would use them.
Why clear up?
Litter makes your school look a mess. It's not only that visitors might get a bad impression; a littered environment has knock-on psychological effects, sapping morale, stirring up discontent and making people feel unsafe.
"Litter is something that people care about in every locality, which affects their sense of well-being," says the minister for local environmental quality, Alun Michael. "There's a continuum between the way people treat their public spaces and the way they behave towards one another, linking environmental issues such as litter, which pull down the feel of any public space, with anti-social behaviour, vandalism and violence."
Hazard to health
But if humans fail to thrive surrounded by litter, rats love it. Fast-food rubbish in particular provides the perfect environment for rats, which in turn spread infection such as Wiles disease, which can cause paralysis.
Bins won't necessarily solve the vermin problem unless they are regularly emptied. "Our outdoor bins are always overflowing, and I watch the rats and squirrels rummaging through them from my classroom window," says one South Yorkshire teacher. "It's not quite the image you want for your school."
Meanwhile, other animals fare less well: litter has a damaging effect on British wildlife, farm livestock and pets. According to a study by Encams, 95 per cent of vets treated animals injured by litter in 2003. These included cuts caused by glass or cans, stomach problems caused by swallowing discarded food, and suffocation caused by stray plastic bags.
Diana Gunnell, a dog owner and former teacher from Lewes, EastSussex, saw life - and litter - from a different angle when walking Ellie, her young lurcher, along a footpath well trodden by school and college students. "It took me a while to twig what was happening, but Ellie was getting fatter.
She would dive into the bushes scenting a half-eaten baguette or chocolate bar." Mrs Gunnell knew it was the route to school and realised that children were throwing away their half-eaten breakfasts as they walked along - "quite disgusting, really". Vigilance and a tight leash were the only solution.
Selling it with sex
Harm to animals might at least make young people sit up and take notice.
Environmental groups have often found teenagers hard to reach and cynical about more traditional litter campaigns. The idea that litter could harm or even kill animals has proved a good way of getting their attention. "Teens are savvy and street-wise and don't want to be talked to like they're babies," says Keep Britain Tidy's marketing director, Sue Nelson. "But confronting them with the idea that their carelessness could hurt animals really seems to make them more concerned."
A more light-hearted approach in recent campaigns has also helped Encams engage with youngsters. "We've gone for something less preachy and more controversial," says Mr Gibson. "Such as a picture of a man holding a chicken, saying 'My cock is huge since I stopped dropping litter', or a woman holding a bin saying 'If you think my bin is big you should see the size of our Fanny's'. We've had lots of requests on the website for more posters, and we reckon students are putting them up in their rooms."
The posters carry a warning that they are only suitable for children aged 15 or over. "They don't appear on bus stations. We've used much tamer ones in public, but with the same level of humour."
The last laugh
Some local authorities take a sterner approach by specifically targeting young litter louts. Last November, Birmingham city council passed a resolution to lower the age of those who could be fined for littering to the age of criminality, currently 10 years old. It now targets areas around schools, bringing in police officers and environmental wardens to survey the area during lunchtime and at home time. Students who continue to litter are cautioned, and if they repeat the offence are served with a fixed notice penalty of pound;50. Non-payment can then result in legal proceedings.
Leading by example
Fines may have a shock value, but campaigners emphasise the value of long-term education to get the message across. A highly publicised 100-day clean-up campaign in Manchester last year managed to tackle 215 "grot spots", serve 1,000 fixed-penalty notices for littering and dog fouling, and complete 200 community clean-ups involving thousands of volunteers. An estimated 50 football pitches' worth of rubbish was cleared.
Schools are also making an effort. Although consideration for the environment is part of PSHE, a focus on rubbish is not always appealing. "A lot of the feedback we get from the students is that these classes are boring," says Mr Gibson. A bit of hands-on activity can make all the difference. With a woodland strip and landscaped gardens, Currie community school in Scotland recently won a Best School Garden award from Edinburgh in Bloom. It also won an Eco Schools Green Flag, and its environmental committee, made up of students of all ages, won a Young Edinburgh Award for Environmental Action. "Every school has a problem with litter," says Eric Melvin, headteacher. "But improving the grounds has given the students more pride in the school and they treat it better."
Another eco school, Canon Burrows Church of England primary school in Ashton-under-Lyne, Tameside, has used its semi-rural setting to advantage.
"It was a bit of a mess, but then the children themselves suggested tidying it up. We've planted trees and made the most of the area. We have a stream running through the grounds that the children are very proud of," explains environmental co-ordinator Andy Clarke. "We have litter-picking days, but even at other times I now get children pestering me for pickers so they can go off and do some clearing up."
Prevention or cure?
Although litter picking might smarten things up for a while, the holy grail is to stop the litter being dropped in the first place. This can be more tricky. "Pupils will often berate someone if they see them dropping litter, but the problem is so endemic that it is not enough," says Mr Melvin.
Many schools try to be positive, rewarding a clean environment rather than sending children litter picking as an alternative to detention. "Cleaning up is purely voluntary," says Joanne Syrett, head of biology and Eco School co-ordinator at Nantyglo comprehensive in Blaenau, Gwent. "Litter picking is not a punishment; it's seen as contributing to a better environment."
If all else fails, why not try the "wow" factor? Twenty thousand children every year, mostly at key stage 2, visit Hazard Alley, an interactive safety centre in Milton Keynes. "It is like a film set," explains Jan Alder, deputy manager. "There are roads and houses and even a building site. The children go through 12 scenarios during a two-hour visit."
Although the emphasis is on playing safely, litter and vandalism are a big part of the visit. "It all contributes to the drip effect of getting them to understand how to be more responsible," says Ms Alder.
The first step to going litter free is to undertake a thorough survey of your school so you can find out where most litter is being dropped, when and by whom. Then you can begin to tackle the hotspots. Some schools have found that shrubberies and hedges not only catch all the litter blowing around in the wind, but are more likely to attract rubbish from pupils who regard them as surrogate bins. Redesignating the tired shrubbery as a wildlife garden and spending money on better plants and landscaping may help change perceptions.
It may seem obvious, but the next step is to take a good look (and smell) at your bins. Are there enough? Are they emptied regularly? Are they in the places where pupils and staff tend to eat and socialise? Are they easy and pleasant to use or are the lids stiff, narrow and grubby? Are they big enough? Getting bins with the right capacity might mean the difference between emptying twice daily or twice weekly. Be imaginative with your bins. Be willing to move them around to see where they are most effective.
Consider customising them with school livery or experimenting with "novelty" bins, where litter is posted through the open mouth of a frog or an elephant: anything to get children into clean habits at an early age.
"Schools require a portfolio of bins for different locations," says Richard Waterhouse, customer services manager at Blackpool-based manufacturer Glasdon. "A smart chrome-rimmed swing bin might be ideal for the reception area, but not for the playground. A wall-mounted bin might be right for the playground but would cause chaos in a crowded corridor."
Think about putting your litter to better use. Improving recycling facilities and encouraging pupils to recycle as part of a wider "going green" project will help tidy up, boost the school's reputation, and may even bring in a few extra pennies. Income from mixed plastics is around pound;40 a tonne and recycled drinks cans fetch around pound;45 a tonne.
At Canon Burrows CE primary there are buckets for composting fruit waste and recycling bins for collecting other waste. "The children enjoy being part of the recycling process; they get upset if it isn't done properly," says Mr Clarke. "We used to see litter as a problem. Now it's an opportunity."
Resourcesl Keep Britain Tidy and Eco Schools are both managed by Encams: www.encams.org.uk; tel 01942 612621l Wastewatch advises on reducing and re-using waste: www.wastewatch.org.uk;tel 020 7549 0331l The recycling consortium can give advice on recycling and composting:www.recyclingconsortium.org.uk;tel 0117 930 4355l Safety Centre, Milton Keynes:www.safetycentre.co.uk; tel 01908 263009
Photographs: Alamy; Getty. Additional research: Sarah Jenkins Next week: School design.
Did you know?
* Schools spend pound;39 million a year clearing up litter
* It is illegal to drop litter. On-the-spot fines of pound;50 can rise to penalties of pound;500 for cases that go to court
* In 2003, 95 per cent of vets treated animals for injuries caused by litter, including cuts caused by broken glass and suffocation caused by stray plastic bags
* The latest Keep Britain Tidy campaign used sexual innuendo to drive home its message, and received requests from young people wanting extra posters
* Litter caused by fast-food packaging grows at a rate of 12 per cent per year