Why I Left the Agency World to Build Trust in Sustainability Claims

Why I Left the Agency World to Build Trust in Sustainability Claims.
After nearly a decade running a purpose-led agency, I realised the marketing tools I’d relied on weren’t enough to tackle the growing trust crisis in sustainability. So I stepped away, and started something new.
Date: August 2025
Read time: 3 mins
Author: Charlie Martin

For most of my career, I worked in marketing. I ran an agency called Gusto, and we helped purpose-led brands shape their narratives, build campaigns, and communicate sustainability in ways that felt bold, clear, and creative. I believed in the work we were doing. I still do.
But over time, I started to feel uncomfortable.
Not because clients weren’t committed. They were. But because the space we were working in, sustainability communications, was getting noisier, riskier, and more fragile by the day. The pressure to simplify complex issues, to lead with impact, to wrap everything in a perfect story… it didn’t always line up with what was actually true.
And when you work in comms, you see that tension up close.
We’d be helping a brand do something genuinely positive, and yet the messaging still felt vulnerable. Were we overstating it? Was the claim going to stand up? Had we crossed an invisible line between confidence and compliance? The truth is, even the most well-intentioned campaigns felt like they were walking a tightrope.
It became increasingly clear to me that trust – in sustainability claims, in brands, in our role as communicators – was breaking down. And we didn’t have the tools to fix it.
The Brief That Changed Everything
The idea for The Anti-Greenwash Charter started with a client project at Gusto. The company was preparing for B Corp certification and wanted help ensuring their sustainability communications were solid – not just from a storytelling perspective, but from a credibility one. They weren’t asking for creative. They were asking for structure. A way to communicate honestly, with confidence, without falling foul of the UK’s new Green Claims Code.
That question stuck with me.
So we tried something new. We helped them develop a Green Claims Policy – a short, transparent document that laid out how their sustainability messaging worked: who was involved, what checks were in place, how evidence was reviewed, and how uncertainty was handled. It wasn’t flashy, but it worked. Internally, it aligned teams. Externally, it gave people something real to trust.
It was the kind of thing I hadn’t seen before, but knew more organisations needed.
Choosing to Step Away
That one policy changed my direction. I realised I didn’t just want to keep creating campaigns. I wanted to help build a new standard – one where sustainability communications weren’t just compliant, but credible. Where communicators weren’t left guessing. Where organisations could lead with integrity, even when their story was still evolving.
So in early 2022, I began to step away from agency life and started The Anti-Greenwash Charter.
The goal was simple: to give people a clear, independent way to approach sustainability communications with honesty and rigour. Since then, the Charter has grown into a not-for-profit initiative supporting organisations with structured reviews, guidance, and a set of principles that take the pressure off guesswork and greenwash alike.

What I’ve Learned
I didn’t leave Gusto because I stopped believing in communication. I left because I wanted it to mean more.
Marketing is still a powerful tool. But when it comes to sustainability, we need more than compelling messages – we need systems that back up those messages with truth. Without that, trust erodes. And when trust erodes, we lose the very progress we’re trying to communicate.
Since launching the Charter, I’ve also been inspired to found truMRK, a service that independently verifies sustainability reports – checking that claims are not only clear, but evidence-based and aligned with regulation. I also continue to host a podcast, The Responsible Edge, where I speak to people across sectors who are trying to lead responsibly in a world that doesn’t always make that easy.
All of this is driven by the same mission: to rebuild trust in how we talk about sustainability. To shift the culture of comms from performance to principle. To support the people – especially in marketing and ESG – who are so often caught in the middle, trying to do the right thing with imperfect tools.
This Work Isn’t About Perfection
If there’s one thing I’ve learned, it’s that responsible communication isn’t about having all the answers. It’s about being transparent about the process. Being willing to say “this is what we know, this is what we’re working on, and this is how we’re making decisions.”
That’s what the Charter helps organisations do. It’s not a badge or a shortcut. It’s a commitment to getting it right – or at least, being honest when we’re not there yet.
And I think that’s what people want. Not perfection. Not green gloss. Just clarity, honesty, and a bit more courage in the way we tell our stories.
For a Truly Sustainable Future
If your organisation believes in doing the right thing — and telling the truth about it — we’d love to have you with us.
📢 Join us as we take this next step.
Become a signatory, shape the future, and show the world what responsible sustainability communications really look like.