2017 is expected to see the first decline in TV advertising revenues in five years according to advertising company GroupM.
It suggests revenues will fall 2.9 per cent year on year in 2017 before stabilising in 2018.
GroupM says it believes UK advertising as a whole is set to see a ninth successive year of growth, and the UK will remain one of the fastest-growing media markets by 2018 despite Brexit.
It suggests that because linear TV is "not naturally a young medium" in 2017 impressions among 16-24-year-olds will fall by 12 per cent, and by eight per cent among 16 to 34-year-olds.
GroupM says some of this loss in viewership "may be overstated" because of "poor measurement of audiences across diffuse TV platforms."
“It’s crucial that the industry deliver better audience measurement to support media planning for performance and brand building alike. As ever, we lend our full support to industry initiatives like BARB’s Dovetail and PAMCo’s AMP," said GroupM UK CEO Nick Theakstone.