The UK CTV market is second only to Canada in terms of highest growth forecast for 2026, according to projections from Guideline, an advertising data and media intelligence company. The forecast comes as UK broadcasters shift focus towards their CTV offerings, while streaming companies push consumers onto ad-supported plans, and advertisers reallocate budgets away from linear TV.
While UK broadcasters have invested considerably this year in strategies to attract more small and medium-sized enterprise (SME) advertisers, Guideline’s figures come from large agency holdcos and major brands, meaning SME spend is not accounted for in the projections. Regardless, CTV spend is forecast to rise 15 percent YoY in 2026, based on billing data Guideline receives directly from large agencies and advertisers.
Sean Wright, Chief Insights and Analytics Officer at Guideline, says this growth is being driven by shifting consumer behaviour, as more viewers transition to streaming services, as well as the natural maturity of the UK CTV market. The introduction of new ad formats will also help to drive ad spend, according to Wright, such as the introduction of Dynamic Pause Ads on ITVX announced in September.
“Some of it is just growth in terms of maturity, and starting to offer more complex ad formats,” Wright tells VideoWeek. “We see this in other markets, like the US and Canada, and haven’t seen as much of in it the UK. But we expect to see it coming.”
Rebuilding reach on TV
The forecast follows a slower year for the UK ad market, based on Guideline’s findings. Total ad spend was up five percent YoY in 2025 to almost £12 billion, marking a slight slowdown from the six percent growth seen in 2024. While the UK saw strong growth in the first two quarters, the second half of the year saw more hesitancy around the state of the economy, while the Autumn Budget raised questions over tax implications and their effect on consumer spending.
This uncertainty tends to push ad budgets to more flexible environments, according to Wright, where advertisers can halt underperforming campaigns with little advanced notice. At the same time, fewer broadcast licenses are being issued each year in the UK as consumers migrate to streaming services, resulting in ad spend on linear TV falling by 12 percent YoY in 2025.
And while CTV ad spend grew 21 percent YoY this year, lower ad loads on BVOD and AVOD services are failing to offset overall declines in TV spending, while fragmentation across the CTV ecosystem is leaving advertisers having to spend more to find audiences they previously reached on linear TV.
“Even if you’re consuming the same amount of content on both linear and streaming, I’m getting more ad revenue on the linear side,” comments Wright. “So even if literally tomorrow, everyone in the UK switched to streaming, there still just wouldn’t be that corresponding same revenue that we see on the linear side. I bet if CTV had similar ad loads, you probably wouldn’t see as much spend shifting away from it. But there’s only so much volume that they can take before they’re literally sold out.”
Breaking down linear budgets
Given these factors, even as viewing shifts towards CTV environments, that linear TV spend is not being reallocated to CTV on a like-for-like basis. According to Guideline data, out of every pound that leaves linear TV, only 21p is reinvested in CTV, with social (19 percent), search (17 percent) and retail media networks (15 percent) all taking a slice from linear TV budgets.
“What we’re seeing is there’s not necessarily a cost similarity between what you could get on linear versus what you could get on CTV,” explains Wright. “If I’m investing in things like live sports, that’s a one-to-one, that makes sense. But if I’m spending on reruns overnight, it’s much cheaper for me to take that money and reapply it to social, where I can get that same bang for my buck, and I can talk to a younger audience at one-third of the price.”
But fortunately for the TV market, the next few years are expected to see a lift from live sports. Spending around the Olympics is forecast to help shore up the linear TV ad market in the UK from Q1 next year, and the World Cup is projected to drive two percent growth in Q2 and Q3. So while 2025 (which itself faced unfavourable comparisons to the men’s Euros in 2024) saw linear TV spending in the UK decline by around 5 percent each quarter, the forecast for 2026 is only down 2.6 percent YoY.
“So still a decline, but half as bad – or maybe 50 percent better, depending whether you’re glass half-empty or glass half-full,” says Wright.
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