Since October 2015, when the 5p charge for carrier bags was introduced, we've got better at remembering to bring shopping bags with us. However, occasionally we all make mistakes - leaving us facing an irritating 5p charge. Fortunately, while we're busy kicking ourselves for forgetting, we're also raising money for charity.
See also: Supermarkets with dress codes - Playboy model asked to leave
See also: Seven ways to spot an online shopping scam
We all have those days when we enter the supermarket with a single bag and the intention of picking up a handful of things - and then leave with a trolley-full, or we walk miles from the car park to the out of town supermarket, before realising our bags are still nestled safely in the car boot. As we count out the extra 5p and seethe at our own stupidity, there's a good chance that we're irritated by stores making money from our forgetfulness.
What many of us forget at these moments is that rather than adding to the fortunes of these big retailers, the government expects them to go some good with the cash. It's not mandatory, but many of the big retailers have already given away a fortune as a result of our forgetfulness.
In the first six months of the scheme at least £29.2 million was donated to good causes.
In the first year, Iceland, Asda, Morrisons and Waitrose joined together to give the money to fund to a new Alzheimer's centre at University College London. Now, they tend to focus their charitable giving on local or environmental causes.
We reveal where the money goes when you buy a bag from ten major retailers.
It operates a charity scheme for local good causes. The Bags of Help scheme invites local groups to apply for money, then asks shoppers to choose from three possible good causes in any month. The money is allocated to each of the three depending on how popular they are - ranging from £1,000 to £4,000. More than 3,500 community groups have been awarded more than £27 million. A fraction of a penny from each 5p goes to Groundwork, which runs the scheme, and almost half a penny goes to communicating to shoppers not to forget their bags.
The supermarket runs a different kind of scheme, because the 5p and 10p bags it sells are bags for life - so they are replaced automatically when they are damaged, and aren't actually part of the government scheme. The exception to this is online deliveries, which can be delivered in single-use bags. They do actually give money to local good causes from the sale of the bags - but they make less profit from the bags - so donate less than the other supermarkets.
Asda runs various charity schemes across England, Scotland and Wales, targeting local charities and community schemes. It doesn't go into much detail, but says: "All the proceeds, less the VAT from these charges will be donated to charities and good causes across the UK."
Morrisons gives any money it makes from single-use carrier bags to good causes - with the Morrisons Foundation being the main beneficiary. This awards grants for charity projects, and match-funds the money that Morrisons colleagues raise for charity. Any local charity can apply for a grant.
Every penny raised from the sale of carrier bags at Waitrose branches in England goes into a community and environmental fund - with no deduction for costs. It means that Waitrose is in effect donating to charity with every bag purchased. It has announced that £1 million will be spent on cleaning up litter - £500,000 through the Marine Conservation Society (MCS), and £500,000 through organisations devoted to clearing up open spaces.
The supermarket donates money from the sale of its carrier bags to an educational partnership with the RSPB. In the first year, it donated £775,000, and it hopes to give a total of £2 million by 2018.
Greggs made £130,000 from the scheme in the past year, and donated the money to the Greggs Foundation - which makes grants to local environmental causes, as well as Keep Britain Tidy and Surfers Against Sewage.
The store passes on the full 5p to Children in Need - plus 5p from each reusable carrier bag sold. Because it makes up the VAT itself, it means B&Q is donating the VAT on each carrier bag to the charity.
The retailer has selected a number of charities to benefit each year - and raises more than £1 million for them through the sale of the bags. It has not publicised this year's charities, but last year raised money for a number of hospices, the Woodland Trust and The Aspinall Foundation.
In Wales, Scotland and England the 5p (minus VAT) is split, with half going to local charities and community causes chosen by individual stores, and the other half going to a selection of national charities including MacMillan Cancer Support, Breast Cancer Now and the Marine Conservation Society.
Of course, when we remember our bags we deserve a pat on the back too, because the number of single use carrier bags issued in the UK has plummeted. In 2014, 7.6 billion of these carrier bags were given away. In the first six months of the scheme's operation just 1.1 billion carrier bags were sold. This is, of course, still an awful lot of plastic bags to be dumped into the environment, but we can at least be confident that by bringing our own bags we're not adding any more to the plastic mountain of waste in the UK.