Tarzan-like howls echo through the woodland of Thetford Forest in Norfolk as students from Langley School in Norwich learn essential safety rules before being let loose on this adrenalin-fuelled treetop challenge.
Go Ape! is suspended high in the trees. The two-hour-plus course consists of six treetop routes. They begin with a basic high-wire traverse with a zip-slide return to ground level, and culminate in a complex series of terrifying rope bridges, swings and scramble-net manoeuvres.
"I've been on the course before and it's very good all round," says Langley's combined cadet force officer Andrew Briggs. "The instructors are very safety-conscious so everyone knows exactly how to work the harness and hooks. Above all, it engenders wonderful team spirit because pupils must help each other.
"It's also great fun - even those who are cautious at first find they can handle the height and the physical demands, so it's a big confidence booster."
Pupils as young as 10 can take part as long as they are above 1.4 metres in height. Under-18s must be accompanied by an adult who is also taking part, and there must be a ratio of one adult to three under-16s. A disclaimer must be signed by the adults in charge of the group.
"It's great to see how children rise to the challenge," says instructor Steve Sutherland. "The equipment is very user-friendly, and children are learning to be responsible for their own safety.
"It's rare for anyone to need the safety harness, but knowing they are safe gives them the confidence to conquer their fears and tackle the physical side of the course."
Go Ape! is open every day from April to September; weekends October, November, March, plus February and October half-terms. Cost per person: 18-plus, Pounds 17; 10-17, pound;12. For more information see: www.goape.co.uk