Children are being encouraged to give up 30 minutes of television and computer games a day to enjoy the outdoors.
The newly formed Wild Network - a collaboration of nearly 400 organisations - is encouraging parents to swap some of their children’s screen time for “wild time”.
Organisers say it is the UK’s biggest ever campaign to reconnect children with nature and outdoor play.
They said that swapping 30 minutes of screen time for an extra half an hour of “wild time” every day would decrease children’s time in front of TVs and computers by 10%.
This could help increase levels of physical activity, alertness and ultimately improve their well-being.
The campaign is being launched with the release of a new documentary film, Project Wild Thing, at more than 50 cinemas across the UK from Friday.
Members of the Wild Network include the National Trust, RSPB, Play England and the NHS Sustainable Development Unit.
Andy Simpson, chairman of the Wild Network, said: “The tragic truth is that kids have lost touch with nature and the outdoors in just one generation.
“Time spent outdoors is down, roaming ranges have fallen drastically, activity levels are declining and the ability to identify common species has been lost.
“New research published last week illustrates the scale of the challenge with only one in five children aged eight to 12 years old having a connection with nature.
“With many more parents becoming concerned about the dominance of screen time in their children’s lives and growing scientific evidence that a decline in active time is bad news for the health and happiness of our children, we all need to become marketing directors for nature.
“An extra 30 minutes of wild time every day for all under 12-year-olds in the UK would be the equivalent of just three months of their childhood spent outdoors.
“We want parents to see what this magical wonder product does for their kids’ development, independence and creativity, by giving wild time a go.”
Suggestions of how to get more wild time playing outdoors in nature include everything from collecting conkers, camping or snail racing to playing leaf snap and counting autumn colour on trees.
A new Wild Time app is also available to show how technology can help give time-pressed families a list of ideas to help get their children outdoors.
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