A new 5p charge for plastic bags is to be introduced in England on 5 October. Here's what you need to know.
Shoppers are to be charged 5p for every new plastic bag they use at large stores in England.
The charge applies only to shops or chains with 250 or more full-time employees.
Plastic bags at airport shops or on board trains, planes or ships, will not be included, and neither will paper bags.
England is the last country in the UK to start charging for plastic bags.
The number of plastic bags handed out by supermarkets in England in 2014 rose to 7.64bn - 200 million more than in 2013.
Figures collected by waste-reduction body Wrap, on behalf of the Department for Environment, Food and Rural Affairs (Defra), show that the figure has steadily increased for the past four years.
In 2010 almost 6.3bn were used.
Campaigners argue that the bags blight streets, spoil the countryside, and damage wildlife, seas and coastline.
Ministers think introducing a 5p charge will stop shoppers using as many new bags, and encourage people to re-use old ones.
The government hopes to see an 80% reduction in plastic bag use in supermarkets, and a 50% fall on the high street.
Over the next decade it hopes the charge will raise:
The charge was a policy championed by the Liberal Democrats in the previous coalition government.
In 2011, Wales started charging 5p per bag and saw a 71% drop in the number used by customers.
But the UK is not alone in trying to limit use.
In 2002, Bangladesh became the first country in the world to ban thinner plastic bags altogether, after they were found to have choked local drainage systems during floods.
Other countries including South Africa, Rwanda, Kenya, China, and Italy followed suit.
More recently Mexico City and the US state of California imposed bans.
No. There are a few very specific exemptions. You will not be charged for plastic bags if you're buying:
While all of the major supermarkets will be charging for plastic bags at their outlets, the price hike will also affect home deliveries.
Most supermarkets are offering a "bagless" delivery service, or are charging a standard flat fee for plastic bags per shop.
Other operators such as Morrisons and Ocado will be charging 5p per bag for deliveries. However, they will also be giving customers back 5p for the plastic bags they return to the company to recycle.
Initially to the supermarkets. This is not a tax and the money raised by the levy will not go to the government.
Retailers can choose what to do with the proceeds of the charge, but they are expected to donate to good causes.
The thin modern plastic bags used by supermarkets are actually cleaner to produce, in terms of greenhouse gas emissions, than paper bags, heavier plastic "bags for life" and textile bags.
In 2011 Britain's Environment Agency published a Life Cycle Assessment of Supermarket Carrier Bags, which concluded that long-life bags have to be reused a number of times - more than 100 times in the case of a cotton bag - if they are to be environmentally a better option than standard plastic carrier bags.
Of course, if a plastic bag is reused then its carbon footprint per use decreases even further.
But although they are technically cleaner to produce, plastic bags do not biodegrade.
According to Professor Tony Ryan, at the University of Sheffield's faculty of science, plastic bags in landfill "exist for at least hundreds of years".
You can also get biodegradable plastic bags but at the moment the government wants to charge for these too.
Defra says it needs to find a way of distinguishing biodegradable bags from standard plastic bags in the recycling process.
Biodegradable plastic bags need oxygen and sunlight to degrade. If they get buried in landfill there is little difference between them and standard carrier bags.
A survey of more than 2,000 people commissioned by Break the Bag Habit coalition - which includes the Campaign to Protect Rural England and Keep Britain Tidy among others - found that 62% of people in England agreed a 5p charge was "reasonable".
Environmental charity Friends of the Earth also welcomed the charge, but said more needed to be done.
The group's chief executive, Craig Bennett, described the move as a "small step" and believed it would "do little to tackle the nation's huge waste mountain".
The plans for the levy were described as a "complete mess" by the parliamentary Environmental Audit Committee last year.
It warned that excluding paper bags and small retailers risked confusing consumers and undermining the effectiveness of the levy - a view also held by the Association of Convenience Stores.