In reply to Robert Durran:
I can't believe I'm reading this! Big wall climbing is way beyond the ability of primary school children and to even think of this is thoroughly IRRESPONSIBLE!
If it wasn't for the fact that this is a well repected Forum subscribed to by responsible adults I would have thought this was a troll.
Base jumping is as very dangerous pass time and even adults should think most carefully before doing it. Untrained children in the age range 6-10 would be at EXTREME RISK.
If you are going to teach children to base jump they need to be introduced to it gradually and from much smaller heights more suitable to their tender age. The best age to start is for the aged 2 and unders. Pushing them off the top of a 6' high step ladder is an ideal start. Aged 3 to 6 can progress to first floor balconies and after a few jumps the older children could be taken up to the second floor. From 6 onwards is a gradual process to get them used to the height eventually up to 3rd and 4th floors.
Only after such intensive introduction should you consider taking them onto big walls.