Recycling: Sugar, bags, cups and changing UK behaviour
BBCWith the Budget looming next week, there is one area that seems likely to merit Chancellor Philip Hammond's attention: plastics.
After the outcry over plastic waste prompted by the BBC's Blue Planet II and a massive response to a government consultation on the issue, it seems likely that the Chancellor will press ahead with using the tax system as a weapon in the war on waste.
This could well involve a package of measures - followed in the coming months by much-needed changes to the UK's recycling system to harmonise and simplify the rules for what can be recycled where.
'Latte levy' anyone?
But there are two ideas clearly in the frame. One is a tax on companies' use of so-called 'virgin' plastics, designed to encourage greater use of recycled materials in manufacturing.
Another is the 'latte levy' - a 25p or more charge on disposable coffee cups.
The first could be passed onto consumers as companies face higher costs of using the targeted materials. But it seems more likely it would end up like the tax on sugary drinks: companies would opt to change their processes to avoid the tax being levied at all, saving consumers the hit (and depriving the Exchequer of the revenue).
The second feels more like the charge on plastic bags. A more direct hit aimed at prompting consumers to make different choices.
And as such, the idea has already attracted some criticism as another blow for hard-pressed consumers trying to enjoy their daily caffeine fix.
BBC Newsnight took a look at why coffee cups have found themselves in this particular spotlight.
Many of the statistics in this area are subject to debate. But the UK is estimated to slurp its way through at least 2.5 billion coffee cups a year (and some groups put the true figure at double that).
And, according to a parliamentary report this year, only about 1 in 400 of those ends up being recycled (or about 0.25%).
That's not because coffee cups can't be recycled. They can.
But the need to separate the plastic liner from the paper fibre cup means only certain facilities can handle them.
So cups need to be collected separately and sent to five facilities around the country, rather than being lumped in with the standard household recycling or ending up in the normal recycling bins you might see on streets or in offices.
The manufacturing industry has set itself a target of getting 85% of cups recycled by 2030.
And the Paper Cup Alliance argues that a levy would only hurt the high street, costing jobs, rather than addressing the logistical blockage in getting cups to recycling facilities that can handle them.
But there are reasons to think that the government could still press ahead.
The number of people carrying a reusable cup with them seems to be very low. Only about 1-2% of sales at the big coffee chains receive the discount on offer for bringing your own cup.
Does that reflect genuine inconvenience of carrying a cup around? Or just human nature?
Research by Cardiff University in this area suggests that discounts don't work very well in changing behaviour, whereas charges do. (This is in line with 'prospect theory' which holds that individuals weight losses more heavily than gains when making decisions).
Ask yourself if a 5p discount on your shopping would have motivated you to carry a bag with you. Perhaps not. But usage of plastic bags fell nearly 85% in the first year after the 5p charge became law.
Coffee cups - intrinsically an on-the-go purchase, often made impulsively - are a tougher nut to crack.
But there is evidence to suggest that the success of the plastic bag charge has spilled over into more public support for similar charges designed to reduce waste.
It would be a headline-grabbing move, in a popular area, where action seems to command widespread support. The coffee cup could next week get its moment in the spotlight.