No cameras, please. T-rex flashes his not inconsiderable teeth at the British press

For a brief second, as it lowered its head towards me and growled, I thought my number was up. Coming face to face with a 23ft tall Tyrranosaurs rex just isn't something CR gets to do all that often. But this week we were invited to the O2 to check out two of the animatronic dinosaurs that will form part of Walking With Dinosaurs: The Arena Spectacular when it tours the country in July. Click through for some scary footage from the day...

The full size T-rex in action. 0.58 mins in – new pants please. Cue nervous laughter

Ten fully mobile, life-size animatronic dinosaurs will perform during the Arena Spectacular show, which is based on the BBC's successful Walking With Dinosaurs TV series. It opens in the UK at Glasgow's SECC on 1 July, having already proved at hit on tour in Australia and in the US.

This bit was extremely loud and quite frightening

While the BBC TV series used cutting-edge CGI to bring the dinosaurs to life, Australia's Creature Technology Company are behind the design of the 3D creatures that feature in the Arena version. They're a team well-versed in creating monsters and aliens for film and television productions.

Their creative director, Sonny Tilders, believes that in creating life-size physical models they're able to replicate the movements and scale of the dinosaurs in a way that CGI, now ubiquitous in filmmaking, simply cannot.

"To make it appear that these creatures are flesh and blood weighing six, eight or even 20 tonnes," Tilders explains, "we use a system called 'muscle bags', made from mesh fabric and filled with polystyrene balls, stretched across moving points on the body. These contract and stretch in the same way that muscle, fat and skin does on real creatures."

A safe distance. Look how big he is!

Indeed, the skin is one of the most important things to get right. "The key to the success of the fluid movements is down to the skin surface itself," Tilders says. "We had to create a type of skin that didn't really exist, that was durable and lightweight. The puppeteers are dealing with a creature with 24 axis of movement, in something that is 1.8 tonnes in weight."

Up-close with the 2m tall baby T-rex

I met two of the team charged with bringing the baby T-rex to life: operator Morgan Durst and puppeteer, Jonathan MacMillan, who actually wears the 2m tall costume.

From inside the baby T-rex, MacMillan can operate the neck, head and mouth, while growls and yelps are transmitted via a speaker hidden in the body. The legs of the dinosaur move in tandem with MacMillan's own as he runs around the floor of the arena.

Puppeteer Jonathan MacMillan with his baby T-rex

The various 'scenes' he'll be involved in during the show usually last 13 minutes at most, as they're very physically demanding. (The time he once managed a 19 minute stint didn't sound too pleasant).

The full show is, of course, extremely tightly choreographed. The full size T-rex we were introduced to weighs nearly two tonnes and has three operators – one inside the body of the dinosaur itself, one back stage controlling the head and tail via a 'voodoo rig', with another working the minor movements of the mouth, blinking the eyes and making those loud, ferocious roars.

T-rex mid-roar

"The aim is to also try and make them move as quick as possible," says CTC chief engineer Trevor Tighe. "CGI has changed many people's expectations: they say, why aren't these things leaping around the stage, hanging off the walls?! But they're doing what we think they would do as animals, not just what CGI will let us do."

The operators of the T-rex: on the left, the man responsible for mouth movements and sound effects; in the middle, the voodoo rig operator who controls the body

While the animatronics technology is certainly impressive – 24 microprocessors, 15 hydraulic rams and 6 motors control the movements of the Torosaur, for example – there's a certain old-fashioned charm in all of this too.

It's billed quite correctly as a 'spectacle' and is, to a certain extent, reliant on a suspension of disbelief. Or, as Tilders nicely puts it, on the magic of "gagetry and robots".

For more information on the tour, which takes in Glasgow, Newcastle, Nottingham, Sheffield, Manchester, London, Birmingham, and Liverpool before returning to London for the final leg, go to dinosaurlive.com.