text: A survey of 2,750 11- to 18-year-olds found one in 10 admitted checking their mobile phones for notifications at least 10 times a night.
  The poll was carried out by Digital Awareness UK and the Headmasters' and Headmistresses' Conference.
  The organisations warn night-time usage of mobiles means pupils are coming to school tired and unable to concentrate.
  They recommend having a "digital detox" and putting mobile devices away for 90 minutes before lights-out or keeping them out of the bedroom.
  Of the 45% of survey respondents who check their phones when they should be sleeping, almost all (94%) are on social media - with a tenth saying they would feel stressed about missing out if they did not check their device before going to sleep.
  Of this group, 75% are listening to music and over half (57%) are watching films.
  A third (32%) of these youngsters say their parents are not aware that they check their mobile device after going to bed.
  The findings also show:
  Charlotte Robertson, DAUK co-founder, said: "One of the biggest topics around at the moment is excessive social media consumption and how it is affecting our physical and emotional wellbeing.
  "A lot of them [children] are waking up sometimes with over 100 notifications from conversations that have happened overnight.
  "They want to be that person that is responding at 01:00, and seen to be quite cool, to make sure they catch the joke - it's a huge driver, that anxiety of wanting to know what's happened."
  HMC chairman Mike Buchanan said: "The data suggests those who do check their phones, they're mostly driven by not wishing to miss out.
  "Clearly there are some times when children are not concentrating because they are tired, and that has an obvious impact on their ability to keep up with what's going on - there is a desire to stay within the group.
  "It's not that this [technology] is all horrible and terrible and that we should all be wringing our hands.
  "It is more a case that here's the reality, let's use it and try to influence the use of technology in a positive way."
target: Almost half (45%) of young people are checking their mobile phones after they have gone to bed, a poll suggests.