Online radio was the fastest growing media channel in the UK during the first quarter of 2026, according to the latest AA/WARC expenditure report. Advertising investment in online radio increased by 22.1% year-on-year, outpacing all other media categories. Total radio advertising also rose by 4.2%, showing the ongoing strength of radio as a multiplatform medium. The AA/WARC forecasts predict that total advertising investment will rise by 8.2% to £50.5 billion this year. The AA/WARC report is recognised as the only source collecting advertising spend data from the entire UK media landscape.