Since 5 October 2015, large retailers in England have been required by law to charge 5p for all single-use plastic carrier bags.
The latest statistics from Defra were made available earlier this week for the 2018-19 period and the results were good.
Looking at the UK’s 7 largest retailers, 70% fewer plastic bags have been issued between the 2016-17 and 2018-19 periods, which is a reduction of 778 million plastic bags.
What struck me most about the above was just how bad Tesco was. In 2016-17, Tesco was issuing more than 3.4x the number of plastic bags than any other retailer (640 million plastic bags per year vs. Morrison’s 191 million). Even when normalised for its overwhelming market share, Tesco was a horrible performer.
Since then, Tesco has managed to reduce plastic bags issued by 515 million, or 80%. This is good progress.
The below chart shows the improvements that each of the 7 large retailers have made over the past 2 years.
I wouldn’t be too quick to compliment Tesco and throw shade at Sainsbury’s though. Tesco was severely obese on the plastic bag front and had a lot of “quick win” kilograms to lose, whereas Sainsbury’s was performing much better than Tesco in 2016-17.
What’s more helpful is to look at the 7 large retailers’ market share vs. their share of plastic bags issued.
What we can see here is that Tesco and Sainsbury’s are leading the way, with both of them issuing fewer plastic bags than you’d expect based on their market share of the 7 largest retailers.
We then see that Marks and Spencer and The Co-operative Group are issuing double the number of plastic bags relative to their market share.
This final reflection is purely anecdotal, but I feel the above conclusions in my weekly grocery shopping routine. Tesco and Sainsbury’s both charge 10p for a sturdy plastic bag that can be reused. Marks and Spencer charge 5p for a plastic bag that is flimsy and easily broken. It’s easy to see why Marks and Spencer issue more plastic bags relative to their market share when they make decisions like that.
Overall, I think this piece of regulation is excellent, predominantly due to its high leverage: a small change in regulation (charging 5p for a bag), that requires minimal measurement and enforcement from government, has resulted in a reduction of more than 750 million plastic bags each year.
Note on my analysis for full transparency
Note: There are many ways to analyse and interpret data like this, and journalists will often manipulate data to get better/worse figures for a story. So I’m linking my analysis here. Feel free to make a copy and play around with it.
I took the Defra dataset and removed all retailers except the largest 7 (Asda, The Co-Operative Group, Marks and Spencer, Morrisons, Tesco, and Sainsbury’s, and Waitrose).
The only information I added was the market share data. I could get the 2018 market share data for all retailers from Wikipedia, except for Marks and Spencer, as it isn’t strictly a supermarket.
Therefore, the method I used to determine Marks and Spencer’s market share isn’t perfect, and I want to acknowledge that. I took their food revenue from Statista, and then derived their market share (3%) by normalising it against Tesco’s 2018 revenue (£57bn) and market share (27%).
I then performed simple sums and percentage change calculations to reach the above conclusions.