- Personalized language across email campaigns at scale
- Subject line optimization drove 20% order rate increase
- Multi-channel rollout across web, app, and push notifications
The Challenge
Translating a 130-Year In-Store Reputation to Digital Touchpoints
Marks & Spencer has spent more than 130 years building a reputation for talking to customers the way customers want to be talked to. Its in-store teams are known for it. But as M&S invested heavily in digital channels, the company faced a harder question: how do you reproduce that tone of voice at scale across web, app, email, and push — for millions of shoppers who never walk into a store?
The stakes were explicit. M&S set a three-year target of 5 billion personalised customer interactions across its digital channels, with hundreds of millions of pounds in growth expected to follow. Its Sparks loyalty scheme already generated rich customer data, and the appetite to use that data was there. What was missing was a way to turn data into language that motivated individual customers on an emotional level — without displacing the copywriting craft M&S was famous for.
"We're one of Britain's — and the world's — best-loved retailers, with amazing products across Food, Clothing, and Homeware. But we're really known for our incredible service and we have an amazing opportunity to bring our customers a similar individualized experience in digital touchpoints, whether that's at home, on the move, or in our stores."
Alex Williams
Head of Growth and Personalisation, M&S
The Solution
A Measured, Collaborative Rollout Across High-Value Channels
In 2019, M&S partnered with Persado and agreed to a two-year engagement. Rather than a big-bang rollout, the team deliberately started on high-value channels to prove that Motivation AI not only worked but won. Persado's platform ran language experiments on hero campaign copy, static website copy, and — critically — email subject lines, where small wording changes have outsized impact on open and order rates.
Each experiment generated multiple variations built from different emotional framing, narrative, and format. Persado's machine learning uncovered which messages moved which customer segments, then fed that intelligence back into a growing bank of insights for future campaigns. Integration with M&S's internal systems was quick, and the engagement quickly felt less like a vendor handoff and more like joint work.
"This was all quite new to us, but Persado really took the time to talk through what the vision was and where we were going. It felt like we were creating a partnership rather than Persado just selling us a product and moving on to the next customer. It was clear that we were trying to build something together."
Rumman Meer
Head of Portfolio — Personalisation, M&S
The Results
20% Conversion Lift and a New Source of Customer Insight
Between June 2021 and December 2021, Persado-optimized email delivered an average conversion rate lift of 20%. As Persado's insight bank grew, the lift climbed further — reaching 34% in December 2021 during peak trading. Subject-line optimization alone drove a 20% order rate increase.
- 20% average conversion rate lift on email campaigns across a six-month window
- 34% peak conversion lift in December 2021 as the insights bank matured
- 20% order rate increase from subject-line optimization
- Hundreds of millions of pounds in revenue driven by the personalisation programme
The numbers mattered, but so did the insights behind them. In one finding that cut against conventional retail wisdom, Persado discovered that M&S customers often did not respond to scarcity and regretful language — phrases like "Only two left" or "Buy it now, quickly." That kind of counterintuitive signal reshaped how M&S thought about tone across campaigns, not just subject lines. The partnership has since expanded to web, app, and push notifications, with tens of millions of pounds in additional incremental revenue expected as the programme runs at full scale.
"It's incredible to see how far we've come with Persado AI on this personalisation journey and it feels like we're just getting started. As we undergo a massive digital transformation as a business, we believe that partnering with companies like Persado will lead to a truly sustainable transformation — one that allows us to thrive for at least another 130 years."
Alex Williams
Head of Growth and Personalisation, M&S
For a retailer whose brand has always rested on knowing how to speak to customers, AI-generated language is not a replacement for craft — it is a way to scale it to every message, every channel, and every shopper.
