I FOUND myself standing on the brink of a slippery ledge the other day, in the middle of Wales, ready to jump into the murky waters of a lagoon 25ft below.

Sweaty-palmed and slightly dizzy, I had actually paid for the privilege of being stuck at the end of the cliff with nowhere to go but down. I hadn't realised just how extreme an 'extreme sports weekend' could be when I signed up for a Wild Wet Wales trip with a few outdoorsy friends. We were in Pembrokeshire, after all. It's not exactly Pepsi Max territory.

But the four instructors who were ominously cornering me to the edge of the cliff were telling me there was no other way to go and all I had to do was take a running jump. "Can't I just walk back down the way I came?", I whined, staring into their disapproving faces.

When I eventually did it, I must have looked like a terrified Disney character who accidentally runs off the edge of a cliff, and looks down below with eyes on stalks before dropping and lying squished below.

I have no memory other than that nauseous feeling of stepping out into nothingness and the sound of the whistling wind around my ears as I lurched forward. I had asked for it and now I was going to get it.

I hit the water hard and bobbed up as a row of faces stared down at me. As I swam to the brim of the lagoon I felt a growing sense of disbelief at what I had just done; me, the city-twerp who has a fear of heights and gets dizzy when hill-walking.

As I looked up, I scoffed at the rest of my group as they stuttered and shrank from the ledge before they reluctantly jumped. It looked so much tamer when you were in the water. Each person who jumped wore a mask of terror which transformed the minute they hit the water into an adrenalin-fuelled smile of relief.

However terrifying it was, I could see how the golden-skinned, fearless instructors had become addicted to it. How many times are you forced to overcome your fears or risk humiliation in front of four extremely good-looking instructors and your 'city' peer group?

It's a matter of converting the fear and nerves into the positive energy you need to make the jump, according to instructor Paul, who held my hand as I quivered on the top of the cliff.

Minutes after my first jump, I felt a sudden fearlessness that made me want to clamber right back up and do it all again. I suddenly felt invincible.

Until I got to the top that is, when the instructors looked at me with grave concern and told me I had jumped so close to the ledge that my head had been less than a metre away from the cliff edge. But now that I was up, there was no other way down but to walk the plank...again.