The guidelines, from the American Academy of Pediatrics (AAP), says children under two shouldn’t have any screen time at all on digital media, apart from chatting via such apps as Skype or Facetime, often used by friends and family living a long distance from each other.

For parents who feel they want to introduce digital media to their toddlers, from the age of 18 months, they should look at high-quality or educational programs and sit with their child so they aren’t viewing alone.

Youngsters who are between two and five should watch no more than one of hour digital media. Again, what they watch should be chosen carefully and children shouldn’t be left to view alone.

Experts are also urging parents not to allow their children to have screen time during bedtime, mealtimes or playtimes, including turning off their own mobile phones so nothing interrupts quality time together.

Those youngsters who are aged between five and 18 ought to have consistency when it comes to how much media is allowed per day.

Because screentime has been found to disturb sleep, children of all ages shouldn’t use devices for the hour immediately before bedtime, and all devices should be kept completely out of their bedrooms.

Dr David Hill, who is a pediatrician and chair of the AAP Council on Communications and Media said there was no use in imposing a blanket ban on screen time because it could be both educational and useful for keeping in touch with loved ones.

He said: “You’ll notice a move away from the idea that you can lump all screen-time together and label it fun or educational or harmful. The ways we interact with screens today are so varied that it doesn’t make sense anymore to start a stopwatch and say; ‘At this point, you’re done’.”

Dr Hill said there was a big difference between a video call with a parent or relative who is serving in the forces overseas, for example, and a child watching inappropriate content alone.

He added: “We have to judge the quality of these different digital experiences and weight them accordingly.”