In October 2021 HSBC put two posters up on bus stops in London and Bristol. One of them said the bank was helping to plant 2 million trees in the UK, enough to lock in 1.25 million tonnes of carbon over the trees' lifetime.
That was true. There was a £4 million partnership with the National Trust behind it, and 90,000 trees were already in the ground. The Advertising Standards Authority banned both posters anyway, on 19 October 2022.
Its objection was to what wasn't on the poster. HSBC's own annual report put the emissions from the oil and gas companies it financed at around 65.3 million tonnes of carbon dioxide a year. The ASA's view was that anyone reading about the trees would want to know about that too, and that without it the poster gave the wrong impression of the bank.
It's a ruling worth having in your head when you sit down to write a sustainability report, because a report gets read in much the same way.
Who actually reads these things
A first sustainability report usually starts life as a list of good news. Somebody remembers the LED lighting project, somebody else has photos from the charity bike ride, and there are solar panels on the warehouse roof now. It all goes in, a designer makes it look nice, and it's published.
You can see why. The work happened and people are proud of it. Nobody is forcing a small business to print its worst numbers in a voluntary report.
But think about who opens the PDF. It might be a procurement manager scoring your tender, or someone at the bank, or an analyst at your biggest customer who has forty supplier reports to get through this week. They've seen a lot of bike rides. What they're hunting for is the stuff that's missing, like the year emissions went up, or a target that was in last year's report and has vanished from this one, or a site that doesn't seem to be in the totals.
The standards expect this of you as well. GRI lists Balance among its reporting principles, meaning the negative impacts get a fair showing alongside the positive ones. The CMA's Green Claims Code has six principles, and the third says claims must not omit or hide important information. That matters more than it used to, because since April 2025 the CMA has been able to fine a business up to 10% of its global turnover for breaking consumer law, misleading green claims included, without going to court first.
Whether consumer law reaches your particular report is one for a lawyer. Either way, the question the ASA asked is a good one to ask of your own draft: would someone who read only this come away with a fair picture of the whole business?
Anyone who has worked in safety will recognise the pattern. A site that reports zero lost-time injuries and stops there hasn't told you much. You learn far more from the site that admits to three and shows you its near-miss numbers and what it changed afterwards.
Start with materiality, not with the cover
Materiality is the dull-sounding step that decides whether the rest of the report is honest. It means working out which issues matter most, both to the business and to the people and places the business affects, and being able to show how you decided.
Do it before anyone writes anything, and don't leave it to one person at a desk. Operations, finance and HR will each tell you something different. If a couple of customers or suppliers will give you twenty minutes, ask them what they'd want to see.
Then let that ranking decide how much space each topic gets. If you run a haulage firm and the report has four pages on office recycling and a single line about diesel, readers will notice, and they'll draw their own conclusions about why.
The numbers people check first
There are a handful of places where an experienced reader goes straight away.
The first is the boundary. Which sites, companies and activities are in the figures, and which have been left out? If you bought or sold a site during the year, how did you handle it? A sentence or two is enough, but it has to be there.
Next is the base year. Choose one and stay with it. When the business changes shape you recalculate the base year and explain what you did, and the GHG Protocol tells you how. What you can't do is quietly switch to a different comparison year because it makes the trend look better. People spot that quickly.
Electricity catches a lot of reports out. The GHG Protocol's Scope 2 Guidance asks for two numbers. The location-based one uses the grid average. The market-based one reflects the contracts you've signed, so a green tariff can bring it down to almost nothing even though the meter reading is the same as last year. Give both, and give the kWh as well so the reader can see what really happened to consumption.
Then there's Scope 3. For plenty of businesses the supply chain and the product in use are much bigger than anything that happens on site, and hardly anyone can measure all 15 categories at the first attempt. That's fine. Say which ones you've measured, which are estimates, and which you haven't got to yet. Readers will forgive "not yet measured". They're much less forgiving when a category just isn't mentioned.
Leave the missed targets in
Put all your targets in one table, with the base year, this year's result and a status against each. Then leave it alone.
It's tempting to drop the one you missed, or reword it until it sounds like progress. Don't. A scorecard where all eight targets are on track looks too good, and people stop trusting the rest of the report. If five are on track, two are behind and one has been missed, and you've written a short paragraph about why and what you're doing next, the five good ones become believable.
The same goes for the five-year data table. If 2023 was a bad year, 2023 stays in.
Be careful what you claim about frameworks
GRI, ISSB, ESRS and the rest tend to get sprinkled through reports as if naming them were enough. Each one means something specific, and some readers will check.
With GRI there are two levels. Reporting "in accordance with" the Standards is a formal claim with a set of requirements behind it. Reporting "with reference to" them is the lighter option. Say which one you're doing and include the content index.
In the UK, the government published the final UK Sustainability Reporting Standards, UK SRS S1 and S2, on 25 February 2026. They're based on the ISSB standards and for now they're voluntary. In the EU, the CSRD was cut back in February 2026 so that it only applies to companies with more than 1,000 employees and more than €450 million turnover. That takes most smaller firms out of direct scope, though it won't stop a large customer sending you a questionnaire.
If you already report energy and carbon under SECR in your annual report, check that the figures match. If they don't, explain why.
Assurance needs the same care. Tell the reader who did it, which standard they worked to and which figures they looked at. Limited assurance over Scope 1 and 2 doesn't make the whole report "independently verified". And if nothing was assured this year, just say so. It's a better look than a vague badge on the back cover.
Five things to check before you publish
- Are your three biggest impacts covered properly, or have your three best stories taken their place?
- Could a stranger work out which sites and companies are in the numbers?
- Is every target there, including any you've missed or dropped since last year?
- For each figure, is there a source file, a named owner and a method someone else could follow?
- Where you've written "verified", "net zero", "carbon neutral" or "in accordance with", does it mean what the standard says it means?
Sooner or later there's a moment like this. It's the Thursday before the board meeting, the draft is with the managing director, and they ring to ask whether the waste figure really has to go in, given that it went up. How you answer that call matters more than anything else in the process.
One for the comments
Nobody at the ASA said HSBC had lied about the trees. The posters came down because of everything else a reader would have wanted to know.
What's the hardest number you've had to put in a report, and how did that conversation go?
Sources
- Advertising Standards Authority, Ruling on HSBC UK Bank plc, 19 October 2022 (ref G21-1127656)
- Competition and Markets Authority, Green Claims Code (CMA146), September 2021
- Digital Markets, Competition and Consumers Act 2024, consumer enforcement powers in force from 6 April 2025
- GRI 1: Foundation 2021
- GHG Protocol, Corporate Standard, Scope 2 Guidance and Corporate Value Chain (Scope 3) Standard
- Department for Business and Trade, UK Sustainability Reporting Standards UK SRS S1 and S2, 25 February 2026
- Council of the European Union, Omnibus I Directive amending the CSRD, adopted 24 February 2026
First published on the HartfellCo LinkedIn page, 9 October 2026.