Retail MediaX 2026: John Lewis and the future of retail media

On May 14, Epsilon took part in Retail MediaX 2026 in London. Joined on stage by John Lewis Partnership to discuss retail media as a core growth engine. The session combined practical lessons from John Lewis’ five-year transformation journey with live audience polling of over 80 brands and retailers. The result? A clear picture of both the progress being made in retail media networks and the gaps that still need solving. Read on to discover the key retail media insights from Retail Media X 2026.

The session kicked off with Epsilon’s Director of Platform and Enablement, Esme Robinson, joining Kaitlin Craig, Partner & Retail Media Proposition Strategy & Development Manager at John Lewis to share a real-world view of what it takes to build a successful retail media network and where the industry still has work to do.

From transformation to traction: the John Lewis Retail Media case study

John Lewis’ success in retail media has been driven by 4 critical principles:

1. Start with strategic alignment

Retail media works when retailer and brand goals are aligned. John Lewis placed brands at the centre of its strategy, using supplier insight to deeply understand their needs and objectives.

2. Build an integrated media offering

Retail media is now a full-funnel ecosystem. John Lewis prioritised:

• Integrating online video (OLV) and connected TV
• Blending onsite and offsite media
• Activating across the full customer journey

3. Let data lead (and test and learn)

Maturity takes time. John Lewis highlighted that the most effective campaigns are driven by data, and the most successful brands are open to continuous testing and learning.

4. Solve measurement properly

Measurement is both the biggest challenge and growth lever. It isn’t one-size-fits-all and the John Lewis view was that measurement breakthrough depends on:

• Achieving closed-loop measurement
• Choosing the right partners like Epsilon
• Aligning metrics to brand objectives (not just ROAS)
• Incorporating in-store data completes a critical missing piece.

What brands and retailers told us: poll results

As part of the discussion, live polls ran with the retailers and brands in the audience. The results highlight where retail media is today and where it’s heading.

Biggest challenges in retail media

When thinking of the biggest challenges that retail media faces, measurement is seen as the number one barrier by a significant margin.

What it means: Solving measurement (especially closed-loop measurement) is the retail media industry’s biggest unlock and to do it, it requires partners that can help you to measure both online and in-store impact.

How differentiated are retail media networks?

When asked on their view on the differentiation between retail media networks, they are largely perceived as similar. Just over 1 in 5 respondents felt there is clear differentiation between retail media networks available today.

What it means: There’s a major opportunity for retailers to differentiate through:

• Data and measurement
• Customer access and unique audience traits
• Media sophistication

Measuring retail media effectiveness

In response to the level of confidence in measuring the effectiveness of retail media, it highlighted that confidence is low and inconsistency is the norm.

What it means: Standardisation and robust measurement frameworks are urgently needed to improve confidence and drive greater investment in retail media.

Activation channels on the rise

When asked for their favourite activation channel, Onsite activation remains the foundation of retail media but nearly half are already looking beyond it. CTV and in-store are emerging as serious growth channels for retail media players.

What it means: Retailers must expand beyond onsite to capture full-funnel demand, particularly as CTV continues to rise.

Retail media undervalues offsite display

A truly revealing insight came when the audience was asked how they perceived offsite display in retail media. It’s apparent that offsite display is being significantly undervalued today and it presents a real opportunity for the future of retail media.

What it means: Brands are recognising the importance of extending retail media beyond retailer environments to drive scale and acquisition.

What next for retail media?

Overall, the session highlighted three priorities for the industry:

• Move beyond onsite
  Success now depends on full-funnel strategies that connect onsite, offsite, CTV and in-store touchpoints.
• Fix measurement
  Measurement remains the biggest blocker—and unlock. Closed-loop, cross-channel measurement is critical to proving impact.
• Differentiate or fall behind
  Competitive advantage will come from stronger first-party data, richer customer access, and smarter activation across channels.

Retail media is evolving fast, those who act on these priorities will define the next phase of growth.

Want to unlock the full value of retail media?

Use the button below to get in touch to see how Epsilon Retail Media can help you deliver closed-loop measurement, activate audiences across channels and drive measurable business growth.