Teenagers are now watching around an hour of YouTube every day, according to a new report which reveals a dramatic change in people's TV viewing habits.
Ofcom found UK subscriptions to streaming giants such as Netflix and Amazon have overtaken traditional pay TV subscriptions such as Sky and Virgin for the first time.
UK subscriptions to Netflix, Amazon Prime and Sky's Now TV have reached 15.4 million – overtaking the 15.1 million pay TV subscriptions which include Sky (excluding Now TV), Virgin TV, BT TV, TalkTalk TV and YouView households.
Research by the broadcast regulator found more than 39% of households have at least one subscription to an on-demand service.
It also found spending by the BBC, ITV, Channel 4 and Channel 5 on new and original, UK-made TV programmes is at a record low – falling from a peak of £3.4bn in 2004 to £2.5bn in 2017.
The amount of time spent watching broadcast television on the TV has continued to decline for the sixth successive year to an average of three hours and 22 minutes a day.
This is down nine minutes (4.2%) on 2016, and 38 minutes (15.7%) since 2012.
There has been a steeper fall among viewers aged 16 to 34, who it was revealed are now spending an average of four hours and 48 minutes across all devices.
Of this total daily viewing time, less than half (two hours and 11 minutes) is spent watching broadcast content, with just under an hour each day spent on YouTube.
The over-65s now watch four times as much broadcast television as children, Ofcom said.
Sharon White, Ofcom's chief executive, said: "Today's research finds that what we watch and how we watch it are changing rapidly, which has profound implications for UK television.
"We have seen a decline in revenues for pay TV, a fall in spending on new programmes by our public service broadcasters, and the growth of global video streaming giants. These challenges cannot be underestimated.
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"But UK broadcasters have a history of adapting to change. By making the best British programmes and working together to reach people who are turning away from TV, our broadcasters can compete in the digital age."
Subscription revenues for online music streaming services at £577m have also overtaken the sale of physical formats such as CDs for the first time which saw a 7% decline to £470m.