Young people are watching more than a quarter less broadcast television than they were five years ago as they turn to on-demand services such as BBC iPlayer and Netflix, a new report shows.
Viewing of broadcast TV fell by 27% among children and 16-24 year olds between 2010 and 2015 according to regulator Ofcom.
Younger viewers have instead embraced free or paid-for on-demand services, with a third of all TV viewing among 16-24 year olds now taking place via that medium, which includes the BBC's service, the ITV Hub and All 4.
Viewing on paid on-demand services such as Amazon and Netflix has especially increased, rising 14 percentage points to 20% in two years, Ofcom's public service broadcasting annual research report said.
The regulator said viewing on TV sets has fallen substantially in the last five years, highlighting "a widening gap between the viewing habits of the youngest and oldest audiences"
Children were watching an average of 151 minutes of TV per day in 2010 but that fell to 111 minutes in 2015, while 16-24 years olds were watching 160 minutes in 2010, which fell to 124 in 2015.
The decline was less the older the viewers got, and was largely unchanged among over-65s.
On average UK viewers watched three hours and 36 minutes of measured broadcast TV a day last year, 26 minutes fewer than five years ago.
Around six in 10 adults now use on-demand services, with 16-24s spending around a third of their daily viewing time watching shows at a time of their own choosing and 36% of their time watching traditional live TV.
This was a stark contract to over-65s, where live TV accounted for 83% of all their viewing and 55-64s, where live TV made up 72% of their viewing habits.
The UK's public service broadcasters' spending on original UK content fell 23% in real terms since 2005, reaching £2.5 billion down from £3.26 billion.
The commercial channels of ITV/ITV Breakfast, Channel 4 and Channel 5 contributed £1.3 billion of the total, while the BBC contributed £1.2 billion.
Funding for children's programmes fell sharply, with the hours of content produced falling from 672 in 2014 to just 580 in 2015.
This was the first time fewer than 600 hours of original UK children's programmes have been broadcast since 1998, Ofcom said.
Spending on this genre was £77 million, down 13% from 2014, the report found.
The public service broadcasters also spent less on new UK arts and classical music programmes in 2015, amounting to £36 million in 2015, down 14% from 2014.
They also spent less on religion and ethics programmes, which were down by 6% to £12 million.
Original UK comedy also decreased by 4%, to £99 million.
Factual programming increased 8% on the previous year to £522 million while drama also improved, increasing 12% on the previous year to £311 million as they showed 416 hours of original dramas.
The main five public service channels accounted for 51% of all broadcast TV viewing in 2015, similar to the last three years, but a decline from 10 years ago when the broadcasters held a 70% share of viewing.
When portfolio channels such as BBC Four, ITV2 or E4 are included, their share of viewing was 71% in 2015.
Jane Rumble, director of market intelligence at Ofcom, said: "Our research shows that UK audiences still watch and value public service broadcasting. But there are significant differences in the viewing habits of older and younger audiences.
"As media and technology continue to evolve, it is important that broadcasters respond to these changes, so they can keep meeting the needs and expectations of viewers."