Keep Britain Tidy, a British anti-trash campaign run by a prominent environmental group, just released a survey of the garbage it found strewn all over 10 of England's city streets, including London. Its headliner finding: McDonald's accounts for 29% of the fast-food trash left across the country. In the city of Birmingham, as much as 41% of the chain-store litter came from McDonald's. Other corporate culprits perpetually inhabiting the gutter included KFC (fourth place) and Subway (fifth place).

The problem is getting worse, too, the campaign reported. Six years ago, 16% of British streets were considered messy, and by the same standards, a quarter now are.

Keep Britain Tidy is trying to use the findings to force the big fast-food chains to be more active in keeping their customers from littering in the first place. I'm not really sure how they're going to do that short of asking customers to bring their own plates.

But the group has floated some early ideas, including giving a discount to people who eat their food at the restaurant or giving small money-back vouchers to people who bring back their used cups, containers, and wrappers for recycling, the way some states' bottle deposits work.While there are some logistics to be worked out -- it's not always easy to process paper that has been covered in food -- a change would not be without precedent. Plenty of offshore restaurants already charge different prices for customers who eat to-go instead of on site, although up to now it has usually cost less money to take food away.

In the past, the fast-food giants have made packaging tweaks as a nod to our environment. Twenty years ago, most McDonald's hamburger stacks came in polystyrene clam-shells that left much to be desired in terms of landfill waste, given that they take 900 years to break down. In the U.S., those have been replaced with cardboard boxes (which break down in about a year), but since McDonald's estimates the number of Big Macs sold annually at 550 million (or 17 every second), even changes like that generate mountains of refuse.

There's no reason to assume the litter findings would be much different here in the United States. With more of us likely to eat cheap junk food instead of paying for more expensive stuff, littering is only likely to increase, and as cities slash budgets, sanitation rounds are only likely to get less frequent. So perhaps Keep Britain Tidy is on to something and it's a smart time to start looking at charging customers different prices for differing uses of an establishment's resources.

Maybe we should start by charging premium prices at the drive-through window. You can bet that most of the hamburger wrappers and shake cups littering the side of the highway were purchased by someone using the drive-through, and not by walk-in customers, who are more likely to throw them away before leaving. Convenience has its price, after all, and I'd love to get a discount for using an honest-to-goodness garbage can instead of making my fry bag someone else's problem.