WHEN we eventually found it, the hidden treasure was worth every hardship we had endured, every drop of blood we had shed.

Miles and miles of rough terrain, ripped and torn by thorns and undergrowth, across treacherous waterways (well, three-foot ditches, anyway) guided only by an electronic gadget giving clues to the hidden cache.

Every moment we were afraid to encounter the treasure hunter's sworn enemy, the muggles, and their terrible creatures that could sniff out the booty before we could.

And all the while, this terrible thirst, knowing a pub was open only a few miles away.

It was only the North Yorkshire countryside. But Indiana Jones could not have been more smug than us when we fell on the treasure known only to a handful of dedicated hunters.

I spent last weekend on the treasure hunt with my pal, Mike, teenage son of our best friends.

It's called geocaching and it is catching on fast all around the world. Basically, it is the search for a hidden hoard using a hand-held global positioning satellite (GPS) device - treasure hunting by satellite navigation.

Just get on to the internet, call up www.geocaching.com and look for the caches hidden in any area.

Key in the co-ordinates on your GPS system and off you go. We set off on our quest by bike.

I'm old fashioned. I took a map and compass, which is just as well because the batteries started to weaken in the electronic navigator.

It was several miles before the device pointed us towards woodland. The gadget is accurate to within about 20 yards, but even then, finding the cache is not easy.

It is normally hidden off the beaten track, away from the prying eyes of the muggles (ordinary people who know nothing about geocaching) and their dogs which can often accidentally sniff out the treasure.

Our first discovery was the Woodland Fortress cache. Even with the aid of satellite, we had to solve coded clues to locate it. And putting your hand deep into the recesses of a gnarled, old tree to see if the treasure is there, is a little disconcerting. You never know what woodland creatures have decided to guard the loot.

But there it was, a Tupperware box containing the treasure. Not gold coins, pearls and rubies. But a tiny Teddy bear, a Dinky toy, a plastic figure and other goodies. And always the notebook and pencil. It's a log book and those who have discovered the cache record the find and leave a comment, rather like a visitors' book in a guest house. You know: "Bed's lumpy, seagulls are too loud."

This one was hidden by a couple named Ros and Paul, serious geocachers by the looks of the other caches they had secreted in the area.

You can take one item from the cache as a souvenir, but you have to replace it with some trinket of your own. Then you have to carefully reseal it and entomb it for the next hunter who comes along.

That's the trouble with muggles. If they discover a cache they don't know what it's all about and carry off the hoard for themselves.

We cycled miles to the next cache and eventually found it high in the split trunk of a tree at the top of a wooded hill. That's where Ros and Paul stumped us. Because they had left in there a series of IQ test clues to the next cache. Each answer gave a co-ordinate to key into the navigator. We got it wrong somewhere, because the dratted machine pointed us at the middle of a main road.

By this time I was seriously dehydrated and feeling the call of the pub. The teenager could have hunted for days more.

Kid's stuff, you might be thinking. What's the point?

Hey, it's great fun. You enjoy the countryside, fresh air and exercise and there's buried treasure at the end of it. How else do you get a 13-year-old away from his computer?