Somehow we had managed to get to the roof of the block. It was one of the tallest structures in the centre of the city - almost six hundred feet of glass, steel and concrete. We had to get past the security guards in the lobby, then find our way through the service corridors to the uppermost floors. Finally we had to break onto the roof itself. But it was worth it.

The entire city lay spread out below us. We could see the streets lit up like orange blood vessels, full of red and white lights that moved along in time with the rhythm of the city's traffic. To the south we could see the dark ribbon of the river, edged in white. All around us were the other towers in the city, thrusting up into the winter night.

We knelt in the light from the aircraft beacon, its pulsing making us look like busy demons. But we weren't demons. We were an unholy trinity of angels preparing to fall from the heavens to the streets below. Carefully we checked our parachutes. Of course we had prepared them ourselves - no BASE jumper would trust another to check their 'chute, and no BASE jumper would dare to suggest otherwise. It was a matter of honour. If anyone was going to end up dead, then it would be their own fault and nobody else's.

The three of us lined up by the parapet. The waist-high metal wall was intended to stop people falling by accident. It was no barrier to us. I looked at my companions. "Have we got this straight?" I asked.

"One left, one right, one straight down the middle. Right?"

I nodded. "We don't want to get in each other's way, do we?"

We stared silently at the streets below, each one of us coming to terms with our own fears. I swallowed hard, suppressing the desire to turn back, to go take the lift back down and go home. If I did, then I would never be able to jump again and experience the thrill of illicit freefall. I climbed onto the parapet, my limbs shaking with the adrenaline that was flooding my body. Did it feel good? Hell, yes it did! I looked to either side. Both my companions had taken up their positions. We were ready.

I held up my right hand. "Right. Three! Two! One! Go!"

And then we jumped.

I pushed myself as far away from the parapet as I could, angling myself down into the void. Instinctively my body assumed a horizontal posture, my limbs spread as wide as possible to catch the air and slow me down. I felt the wind tug at the drogue chute in my hand. I could just have held on, enjoying the terminal rush of velocity, but I didn't. The wind ripped the cord away from me, and there was a sudden snap of nylon.

The harness dug into me, threatening to cut me in two. My legs swung down and I slowed. To either side I saw the 'chutes of my friends inflating. Slowly, we drifted down into the street. I started running in mid-air, ready to take the impact of landing.

There was a shout from a side street: "Are you OK man?"

"Yeah! We're good! C'mon!"

Our ground crew came running out of the shadows, ready to bundle us and our 'chutes into the waiting van. We knew the police would be on the way soon, and we didn't want to be here. As we fell into the cargo bay, I turned to my friends.

"What a rush, eh? What a rush!"