"Can I do this? I might not be able to you know. What if I bottle it and have to turn around? A walk of shame back down the stairs..."

These were my very real thoughts as I stood strapped in at the top of the Zip Now tower in London's Archbishop's Park.

It's billed as "the world's longest, fastest city centre zip wire".

On a drizzly Sunday morning, my wife and I had gone through the registration process and safety briefing, before getting 'kitted up'.

The Zip Now staff were really good all the way through the experience. Harnesses are all lined up in a row for each 'group' of riders to step into.

You're given clear, step-by-step instructions of how to put the harness on, and which buckle goes where and which strap does what. And you're helped to do it all properly.

But most importantly, your kit is checked, double-checked and triple-checked. Firstly, by the team at the registration building. Secondly, by another member of staff at the base of the launch tower. And lastly, by the team at the top - who are apparently talking to you, but you may be unaware of this due to the buzzing in your ears, wobbly legs and vague feeling of nausea as you look out over London and the Thames from 35m up.

That's the combined height of NINE double-decker buses. Just the nine... so yes, by the time you've got to the top of the launch tower, you've climbed the equivalent of more than nine sets of steps inside a bus. My legs progressively turned to jelly as my quad muscles threatened to ping.

And then you're at the top. And you can see the tree tops. And the zip wire. Which is 225m-long.

There's a bit of waiting as the riders in front of you launch themselves into the air. This is not a good thing. See my thoughts at the top of this page.

Zip Now is located in Archbishop's Park

My wife didn't know we were riding Zip Now that morning. What a lovely and romantic surprise I'd arranged! The hope was that we'd ride the thing side by side. After all, we'd managed a tandem bungee jump over Lake Taupo in New Zealand.

So then it was our turn to step forward. The platform narrows as you're hooked onto the wire and your knuckles begin to turn white on the handle.

There are three metal steps for you to gingerly tread down. And then... nothing. Absolutely nothing. Thin air. And that 35m drop to the ground. So what do you do? How do you approach the 'launch'?

I guess I just 'went for it'. My wife was more tentative as she navigated the final steps on her bum!

"Just go," she told me. And so I was off.

To be honest, it all went by in a bit of a blur. It's over in 30 seconds or less. But what an exhilarating feeling. You're basically flying, right? Although with gravity obviously making sure you're heading downwards.

The team at the other end reel you in along the remaining wire. You try to get some purchase with your feet on the metal platform, but your legs have gone somewhat wobbly. And the adrenaline rush means you're a bit all over the place, breathless as a staff member asks if you're alright. "Schnumbalub" - that might be your reply.

But you've done it and you can now get unhitched and walk happily back down to terra firma.

Or... you could just take the Mega Drop down to the ground. It's a freefall jump from the landing tower, which "allows riders to take a more stylish exit than simply descending the stairs".

Zip Now says: "The Mega Drop requires riders to take a step into the void, with a stomach-flipping freefall followed by a gradual slowing towards the ground. It’s a bit like a bungee jump without the bounce. Jump from a height of 15m and let Mega Drop catch you. It’s the perfect ending to your Zip Now experience."

Perfect? Hmmm. Well it's certainly different. Stepping off into the Mega Drop goes against every human instinct ingrained into your mind and body.

But I did it. I was far from stylish, however. I would have loved to follow in the footsteps of Indiana Jones in The Last Crusade - taking the 'leap from the lion's head' on the 'Path of God' towards my own Holy Grail (the ground).

Except I was minus the bullwhip and fedora hat. And looking slightly more balding and overweight than Harrison Ford during peak Indy action in the late 1980s.

The lady next to the inflatable landing pad down below said she liked the way I took on the Mega Drop - "just going for it". Well, only after a few seconds of hesitation. And grimacing and clenching all the way down. But if it was good enough for her.

The Zip Now experience is continuing until September 9 this year. "Remaining slots are selling fast... book now to avoid missing out." So get yourself along. It could just be the ride of your life.

For full information about Zip Now, visit the website.

Zip Now
Safely back on solid ground