The decrepit wooden footbridge bounced and swayed gently as we crossed the swollen river below. Narrow and rickety, the bridge had one wire grab rail but absolutely nothing on the other side. Halfway across Jake, my four-year-old son, turned around and looked at me for reassurance. My hand was secretly hovering millimetres from a strap on his rucksack, so I could grab him if he looked like he was slipping. I gave him a confident smile and he beamed conspiratorially. ‘Keep your eyes ahead,’ I said. ‘Focus on your feet and the bridge.’

He turned back and made it across with a final leap and a laugh. Crossing the bridge felt nicely risky, and also wonderfully naughty, even though we were nowhere more exotic than the River Dart in Devon. Our little gang of five adults and five children had thrown caution to the wind and ignored a tiny sign on one side of the bridge reading ‘Private property – keep out!’. ‘Pah!’, we said. The sign was so small it was an invitation to cross.

We hopped off the bridge onto a small island in the river, less than an acre in size, then wandered along a short woodland path for just a few moments, carefully avoiding bluebells. We emerged into a glade with a sandy beach, a perfect stretch of river and a stunning rocky cliff on the other side that soared up to 20 metres high.

It was stunning, totally idyllic and completely unexpected. Our picnic was magnificent, washed down with strong tea, courtesy of my Kelly Kettle. Then Chris, an adventurous dad to two boys, produced the perfect childcare tool for any age group – a thick slackline.

Within a minute it was ratchet-strapped between two trees and the kids spent a busy hour balancing, toppling into thick grass, and laughing almost hysterically. It doesn’t take much to create a load of excitement, and rarely have a group of children had quite such a wild time within a few hundred metres of a car park.

Those few hours by the River Dart were a perfect microadventure, a fantastic idea popularised by the author and adventurer Alastair Humphreys. He recognised that not everyone has the time, or the inclination, to spend three weeks traversing the Kinabatangan River in Borneo, especially with tricky kids.

Humphreys extols the virtues of shorter experiences, including the five-to-nine adventure, in which stressed office types head to the hills for a quick, rewarding overnight camp, and then get back to their desks in the morning. Wage slaves deserve excitement, of course, but microadventures are ideal for parents with children.

They can be short, surprising and spontaneous, which keeps the kids on their toes and makes a parent seem really fun. The best tools for a microadventure include a slackline, a campfire, tents, bivvy bags and ultra-light waterproof sleeping sacks for a wild camping experience. Children absolutely love them. Have a look at Alastair’s website for more ideas (alastairhumphreys.com). Personally I love, ‘Grab a map. Close your eyes. Point. Go’. Nice and simple!

Whether you’re stuck in a city or already on a holiday, there’s always time and space for another memorable microadventure. Get a slackline and make somewhere secluded your adventure playground.

To read more of Simon’s columns, visit familytraveller.com/authors TV adventurer and author Simon Reeve has presented multiple award-winning BBC TV series, including Australia, Sacred Rivers, Tropic of Cancer, Indian Ocean and Caribbean. simonreeve.co.uk