The National Trust has launched a nationwide campaign to encourage sofa-bound children to take to the outdoors and enjoy classic adventures from skimming stones to building dens.

The ‘50 Things To Do Before You’re 11¾’ initiative is in response to a report commissioned by the National Trust which highlighted research that fewer than one in ten children regularly play in wild places compared to almost half a generation ago, a third have never climbed a tree and one in ten can’t ride a bike.

The charity’s 50 Things To Do Before You’re 11¾ campaign provides a checklist for under-12s (and those who are young at heart) including everything from running around in the rain and bug hunting, to setting up a snail race, damming a stream, flying a kite and making a (delicious) mud pie.

To help bring to life these simple pleasures, the Trust has formed a group of Elite Rangers who will share their expert tips on enjoying outdoor adventures and their enthusiasm for encouraging children to play alfresco.

The five rangers, all Trust staff, come from across the UK and range in age from 29 to 49.

They include a 6ft 3” tree climbing expert, who has scaled 50 metre-high trees, (a.k.a. Tree Man), Captain Skim who can skim a stone over 26 times and Midas the treasure hunter. The other rangers are Den-Boy, an outdoor hideaway-building champion, and a minibeast expert (aka The Bug Catcher).

The fantastic five will be offering top tips on their chosen skill to the nation’s children over a Free Weekend (21 and 22 April) when the National Trust will open up over 200 of its houses and gardens for free over the weekend, as well as all the countryside spaces it cares for, which are always free access.

Kids can pick up a free 50 Things To Do Before You’re 11¾ scrapbook from participating properties – and start ticking off their outdoor adventures to do list.

Plus, the fun can continue at home by visiting nationaltrust.org.uk/50things where children can fill in their completed activities and earn points towards their very own explorer badge.

Tony Berry, visitor experience director of the National Trust, said: “Our Elite Rangers are a fantastic bunch, with bags of enthusiasm for the outdoors and what it can offer kids.

"We’re hoping that the nation’s children will embrace the 50 things and start having their very own outdoor adventures with their family, with our Free Weekend the perfect opportunity to get outside in the fresh air.”

National Trust Elite Ranger Captain Skim, Mark Astley said: “My top tips for stone skimming are to find some flat water, like a lake or sea on a calm day. "Choose your stone carefully – the smoother, rounder and flatter the better. Next perfect your stance, bend your knees into a squat position with one foot in front of the other about a foot apart.

"Steady yourself by putting your non throwing arm in front of you and point your finger in the direction you want the stone to travel. Hold your stone throwing arm behind you and then bring forward - throw hard and low so it spins quickly across the top of the water.

"My personal best is 27 skims and I’m still trying to beat that. ”

The 50 Things to Do Before you’re 11 ¾:

1. Climb a tree.

2. Roll down a really big hill.

3. Camp out in the wild.

4. Build a den.

5. Skim a stone.

6. Run around in the rain.

7. Fly a kite.

8. Catch a fish with a net.

9. Eat an apple straight from a tree.

10. Play conkers.

11. Throw some snow.

12. Hunt for treasure on the beach.

13. Make a mud pie.

14. Dam a stream.

15. Go sledging.

16. Bury someone in the sand.

17. Set up a snail race.

18. Balance on a fallen tree.

19. Swing on a rope swing.

20. Make a mud slide.

21. Eat blackberries growing in the wild.

22. Take a look inside a tree.

23. Visit an island.

24. Feel like you’re flying in the wind.

25. Make a grass trumpet.

26. Hunt for fossils and bones.

27. Watch the sun wake up.

28. Climb a huge hill.

29. Get behind a waterfall.

30. Feed a bird from your hand.

31. Hunt for bugs.

32. Find some frogspawn.

33. Catch a butterfly in a net.

34. Track wild animals.

35. Discover what’s in a pond.

36. Call an owl.

37. Check out the crazy creatures in a rock pool.

38. Bring up a butterfly.

39. Catch a crab.

40. Go on a nature walk at night.

41. Plant it, grow it, eat it.

42. Go wild swimming.

43. Go rafting.

44. Light a fire without matches.

45. Find your way with a map and compass.

46. Try bouldering.

47. Cook on a campfire.

48. Try abseiling.

49. Find a geocache.

50. Canoe down a river.