ON an industrial estate near Glasgow Airport, a ferocious battle is unfolding. There is a deafening crash as sparks fly and the acrid smell of sheared metal fills the air. Out in the arena, two robots are locked in deadly combat as a baying crowd roars its approval.

It is a gladiatorial scene which feels akin to wandering into a post-apocalyptic wasteland where the machines have taken over and only the strongest will survive.

Welcome to Robot Wars. The cult BBC television series is back after a 12-year hiatus and this time around it is bigger, badder and even more brutal.

The premise is simple: teams of amateur robot enthusiasts pit their homemade creations against each other in the hope of being crowned 2016 champion.

They must not only outmanoeuvre each other, but also a fearsome quartet of "house robots" while surviving a series of hazards including fire and spikes. Battles are judged on aggression, damage and control.

Backstage the tension is building. Tucked behind a curtain is the "dressing room" for four menacing beasts: the house robots. Final preparations are being made to Sir Killalot (a colossal brute with rotating drill lance and terrifying skull face) and Shunt (a plough armed with a titanium axe).

Dead Metal (pincers and a whirring circular saw) and the deceivingly sweet-sounding Matilda (pneumatic flipping tusks) are already being wheeled out ready for the next bout.

In the pits, there is a heady mix of perspiration, passion and pride as 40 teams make last minute alterations with soldering irons or tinker with circuit boards. Their inventions have kooky names such as Kan-Opener, Thor, Gabriel, Glitterbomb and Kill-E-Crank-E.

They include Gary Cairns, 28, from Mintlaw, Aberdeenshire, who is team captain for PP3D Robotics. Gary was involved in Team Typhoon – which won series seven of Robot Wars – as a teenager.

He gained a masters in mechanical engineering from Strathclyde University and became a drilling engineer for BP before setting up his own 3D printing company last year.

"I have real history with Robot Wars," he says. "All the way through university I was still involved in the live events circuit. I have watched Robot Wars since the very first series."

His team-mates are fiancee Sarah Dennis, 26, who runs a farm, and their friend Jamie McHarg, 28, a domestic gas engineer.

"This is very much Gary's thing," says Sarah, smiling. "He is a force to be reckoned with and sometimes gets a bit carried away.

"Gary is willing to trash the machine for a good fight, but he has the skill and ability to put it back together. Every time he gets better at it and builds a far improved version."

An electric atmosphere is building around the vast, purpose-built arena as spectators wield giant foam fingers and hold aloft laminated posters of their favourite bots.

There are pulsating lights and throbbing music. The roboteers wave like gods from the control box.

Goosebumps rise as the clock counts down. 3-2-1 … Activate! The robots come together like prize fighters as they attempt to flip, crush or rip their opponent to shreds.

The iconic man vs machine battle show has certainly come a long way from its early days.

The rebooted Robot Wars is fronted by Dara O'Briain and Angela Scanlon, while the judging panel comprises Dr Lucy Rogers, Professor Noel Sharkey and Professor Sethu Vijayakumar – all respected academics in their fields of mechanical engineering and robotics.

Presenters Dara and Angela are as enthusiastic as any of the competitors.

"I don't think there is anyone who wasn't aware of Robot Wars and the cult around it," says Angela, who is a regular film presenter on The One Show and co-hosted live coverage of T in the Park. "The fans never went away. They didn't forget about the show and it feels like it has lived on."

Many of the contestants were avid viewers in their teens when the original show aired. Others are veterans that have featured in the past and returning for another shot at glory.

"There is a father and daughter team and the girl was a Robot Wars baby," says Angela. "Her mum went into labour while watching her husband fight. She is back with her dad and his old team-mate. She is a ballerina but also into robots. It is kind of heart-warming and totally bonkers."

Despite the fierce competitive nature, there is a camaraderie among the amateur roboteers. "In one fight a robot got destroyed – taken apart bit by bit – and there were fragments everywhere," says Dara, who also hosts BBC panel show Mock The Week.

"Later there were four or five different teams gathered around one table, welding pieces back together, to help get it out to fight again."

Although it's not all gooey marshmallow moments as Angela is quick to point out.

"That community aspect is sweet, but then you talk to them in the pits as they are getting ready and the most wonderful people turn evil in the flip of a switch," she says. "There are very few formats that allow for people to talk about pounding and killing with such enthusiasm."

Dara nods in agreement. "I think it's about metal on metal," he says. "The fact there is a human part to it is great because there is a lovely back story to it all, but then they go into a closed-off arena surrounded by two layers of bulletproof glass with the pure intention to destroy each other."

As for what makes Robot Wars such addictive viewing, Angela hits the nail on the head. "You are completely immersed in their world," she says.

"They've spent three years building a robot, painstakingly putting it together and it takes three seconds to demolish it in front of everybody. You can't help but be totally engrossed in that."

Robot Wars returns to BBC Two, 8pm, on July 24