The majority of pupils now own a mobile phone by the age of 7, according to a new study.
The devices have become a fundamental part of life for most young people, it indicates, with many admitting they are fearful of being without their phone and a significant proportion sleeping with it by their bed.
Overall, pupils now spend, on average, around three hours and 20 minutes each day messaging, playing games and being online, the report by Childwise says. The amount of time was down slightly compared with research last year.
Pupil mobile phone use
Mobiles are the devices that pupils are most likely to use to access the internet, it says.
Researchers said the findings show the extent to which phones can "dominate children's lives".
The report, based on a survey of 2,167 UK five- to 16-year-olds, suggests that 53 per cent of children are now mobile phone owners by around the age of 7.
It goes on to say that by age 11, 90 per cent of pupils have their own device, and once pupils are in secondary school, phone ownership is "almost universal".
Almost two in five – 39 per cent – of those questioned said they could not live without their phone, up from 33 per cent last year.
Secondary-aged pupils – aged 15 and 16 – are most concerned about being without the technology, the report says.
More than half – 57 per cent – of all the children surveyed said that they always slept with their phone by their bed, while the same proportion admitted they did not know what they would do if they lost their device.
And just under half – 44 per cent – said they would feel uncomfortable if they were somewhere without a phone signal, while 42 per cent admitted to being "constantly worried" about running out of charge.
Simon Leggett, research director at Childwise, said it can be difficult for mothers and fathers to monitor children's use of technology as "the mobile phone is such a private and personal technology".
"The moment a child owns a mobile phone, it can be a challenge to monitor what your child is accessing online because it's such a private technology that most keep, literally, close to their chest," he said.