BARB's Q4 2025 Establishment Survey data is out, and for UK advertisers still treating connected TV as an emerging channel, it is time to update that view. The data makes it clear that ad-supported streaming is no longer approaching scale. It is already there.

20.6m UK homes, nearly 70% of the country, now have access to at least one SVOD service. The question for brands is not whether streaming audiences are big enough to justify advertising investment. It is how to reach them efficiently, and with what data.

The ad-supported tier is now the mainstream tier

The most strategically significant shift in the BARB data is not overall subscriber growth. It is the rapid expansion of ad-supported viewing within the existing subscriber base.

Netflix grabbed headlines in Q4 with 18m UK households, its third-best growth quarter on record, helped considerably by the Stranger Things finale driving 440,000 new subscribers. But the more important number for advertisers is that 38% of Netflix homes are now on its ad tier, equating to 6.9m UK households. That is up from 6.1m in Q3, an increase of 800,000 homes in a single quarter. Year-on-year, Netflix's ad tier has grown 47%.

Amazon Prime Video tells a different story, and in some ways a more powerful one. Prime Video is present in 13.8m UK homes, and 87% of those households are on the ad-supported tier. That translates to 11.9m UK homes that are reachable through Prime Video advertising. The reason for that 87% figure lies in Amazon's approach: rather than offering ad-free as the default, Prime members are placed on the ad-supported tier unless they actively opt up to a paid ad-free plan. The result is an ad-supported audience at a scale no other streaming platform currently matches in the UK.

Disney+ is moving in the same direction, with 35% of its 7.6m UK households now on the ad tier, up from 30% the previous quarter. Year-on-year, Disney+'s UK ad tier has grown 73%.

What this means for advertisers

The combined picture is striking. Across just three platforms, Prime Video, Netflix and Disney+, UK advertisers can now reach ad-supported audiences totalling approximately 21.4m homes. The demographics skew toward households that are actively choosing content, are engaged with what they are watching, and are demonstrably willing to accept advertising as part of that experience.

This is premium, brand-safe inventory at genuine scale. The growth in ad-tier penetration across all three platforms suggests it will continue to expand through 2026.

One platform to reach them all

The operational challenge of reaching audiences across multiple streaming services has historically required separate deals, separate buying processes and separate measurement frameworks. That complexity is now, in large part, solved.

Prime Video, Netflix and Disney+ are all accessible programmatically through Amazon DSP, alongside a growing list of other premium inventory including DAZN, Paramount+, Spotify, Samsung TV Plus and more. 

That means advertisers can reach a substantial portion of the UK's ad-supported streaming audience through a single platform, with Amazon's first-party shopper data informing targeting and Amazon Marketing Cloud providing closed-loop measurement from exposure to purchase.

The fragmentation that made CTV planning complicated is being consolidated. Amazon DSP is the most significant beneficiary of that consolidation.

The opportunity for UK brands

At Vector, we help brands navigate the full Amazon ecosystem, including the growing range of streaming inventory accessible through Amazon DSP. The BARB Q4 data confirms what we are already planning around: the audience is here, the ad tiers are growing, and the infrastructure to reach them efficiently is in place.

The brands that build CTV into their media strategy now, rather than treating it as a future consideration, will be the ones with the strongest audience relationships as streaming continues to displace traditional broadcast viewing.

Want to understand how to reach UK streaming audiences through Amazon DSP? Talk to the Vector Retail Media team.

"Across just three platforms, Prime Video, Netflix and Disney+, UK advertisers can now reach ad-supported audiences totalling approximately 21.4m homes."