UK digital ad spend hit £21.2bn in six months. Retail media grew fastest at 32 per cent

Brands put £21.2bn into digital advertising in the UK in the first half of 2026. That is 13 per cent more than a year earlier. IAB UK and its research partner MediaSense published the half-year figures on 29 September.

Search takes £9.1bn but grows slower than the market

Search is still the largest line at £9.1bn, or 43 per cent of all digital spend. It grew 10 per cent, three points below the market. Video rose 18 per cent to £5.1bn. About one third of that video money now goes to TV+, the streaming services sold alongside broadcast.

Retail media adds 32 per cent and reaches £2.0bn

Retail media was the fastest riser. Spend on ads bought inside shops and their apps reached £2.0bn, up 32 per cent. IAB UK says retailers are being brought into planning earlier, not only at the end for a sales push. The same shift is visible elsewhere in Europe, where Poland’s retail media market is worth about 2 billion zloty.

Programmatic now carries £17.2bn of the £21.2bn

Automated buying accounted for £17.2bn, or 81 per cent of the total. A year earlier the share was 78 per cent. Programmatic has stopped being one channel among several and has become the way most of the market works.

Elizabeth Lane points back to 2020 and £16.5bn

Elizabeth Lane, head of insight at IAB UK, said the 2020 comparison shows the scale of the change. The whole of 2020 brought in £16.5bn. Six months of 2026 brought in £4.7bn more than that.

The study also asked buyers what worries them. Economic uncertainty came first, named by 70 per cent. AI and automation followed at 37 per cent, and measurement at 30 per cent.

The forecast is 12 per cent for the year and £50bn by 2027

MediaSense expects 12 per cent growth across the whole of 2026, which would take the UK market towards £50bn in 2027. Read that against the other numbers on the table: IAB lifted its US forecast to 12.3 per cent this month, while the German market grew 0.9 per cent in August. If you plan across those three countries, the same budget increase buys very different growth, and the UK plan needs the biggest uplift to stand still in share terms.