UK advertisers spent £21.2bn on digital advertising in the first half of 2026, almost £5bn more than they spent during the whole of 2020, according to the latest Digital Adspend study from IAB UK and mediasense.
The comparison shows how much the market has expanded in a relatively short period. In 2020, UK digital ad spend stood at £16.5bn for the full year. Six years later, advertisers are investing significantly more than that in six months, says IAB UK. Spend grew 13% year on year in the first half of 2026, but the figures also point to a shift in where that investment is going, with retail media and video growing ahead of the wider market.
Retail media was the fastest-growing area, rising 32% to £2.0bn, while video increased 18% to £5.1bn. Search remains the UK's largest digital advertising channel by some distance, reaching £9.1bn and accounting for 43% of the market. But with search growing 10%, below the overall market rate, the figures show investment spreading across a wider range of digital environments.
Retail media is a particularly clear example of that change, added IAB UK. Interviews conducted for the study suggest that advertisers are increasingly looking beyond its roots as a performance channel close to the point of purchase. As retailers build out their advertising propositions and make greater use of first-party data, retail media is finding a place earlier in the planning process, giving brands more opportunities to reach and influence customers before they are ready to buy.
Video is changing too. A third of the £5.1bn invested in video in the first half of the year now goes to TV+, as streaming continues to attract audiences and advertising investment. Connected TV inventory is also becoming easier to plan and buy alongside other digital formats, making the traditional distinction between television and digital video increasingly less clear for advertisers.
The way this growing market is bought has also shifted, IAB UK continued. Programmatic accounted for £17.2bn in the first half of 2026, equivalent to 81% of all UK digital advertising investment and up from 78% a year earlier. Rather than being a distinct part of digital advertising, automated trading is now the way the vast majority of the market operates.
The growth comes despite advertisers continuing to navigate a challenging economic and regulatory environment. Economic uncertainty was the most commonly cited challenge in the study, appearing in the top three for 70% of respondents. AI and automation were cited by 37%, while measurement was highlighted by 30%. Despite these pressures, mediasense forecasts growth of around 12% for 2026 as a whole, in line with previous forecasts, putting the UK digital advertising market on course to reach £50bn by 2027.
Elizabeth Lane, head of insight at IAB UK, said: “The comparison with 2020 really brings home the scale of change. Back then, £16.5bn represented a full year of digital advertising investment. We’re now seeing £21.2bn invested in just six months. But this isn't only a story about digital getting bigger. Where that money is going is changing too. Retail media is growing rapidly, a third of video investment is now going into TV+, and programmatic accounts for more than four-fifths of digital spend. Advertisers have far more ways to reach people digitally than they did even a few years ago, and we're seeing that reflected in where budgets are moving.”
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