"I'm blind!" screamed PJ on teen-soap Byker Grove in 1992 and a generation was warned forever of the dangers of paintballing without goggles.

Seemingly a huge issue at the time (half the world's tweens were stumbling about like in Day of the Triffids), to this day, thanks to Byker Grove, I've never been blinded in a paintballing accident (I'm usually too busy trying heroin, which Zammo on Grange Hill warned about. Sadly, I didn't watch Grange Hill).

PJ and his chum Duncan, aka Ant McPartlin and Declan Donnelly, went on to have a pop hit, Let's get Ready to Rumble, about their days as hardcore street brawlers. Then they left the mean streets entirely and evolved into dual-headed light-entertainment hydra Ant-and-Dec – a partially split amoeba, which sleeps coiled around itself like the Yin and Yang symbol, suckling on the marrow of Vic and Bob, and gripping the future of light entertainment in its tendrils.

Ant-and-Dec are in complete control of their medium and, by extension, Britain, which they chuckle over despotically every Saturday. They also appear on two Irish television stations simultaneously, bilocating like St Anthony of Padua. UTV Ireland runs the 2015 version of Ant-and-Dec's Saturday Night Takeaway, while TV3 has the 2013 series which they cheekily air 20 minutes earlier.

Bantering guest

It takes Ant-and-Dec to take on Ant-and-Dec. And it’s hard to tell Olden Days 2013 Ant-and-Dec from modern 2015 Ant-and-Dec, for they are ageless, their faces no doubt etched in the stone of Stonehenge. Both shows begin with a bantering guest announcer – Neil Patrick Harris in this week’s 2015 episode (Harris is to host the US version of this show, albeit with just one body) and Terry Wogan in 2013 (he also started in broadcasting as two separate people, Terry and Wogan, before they melded together completely in 1976).

Then there's a show-trial. Ant-and-Dec alight on audience members and reveal that they've been in their houses and know their peccadilloes. In the UTV Ireland version, there's a public trial adjudicated by ITV's Judge Rinder. On TV3, Olden Days Ant-and-Dec relocate a woman's entire sitting room to the studio, dispatch a besuited troll doll (Deal or No Deal's David Dickinson) to rifle through her drawers and send her belongings to the set of Neighbours. They're like a crazed monarch, really.

Both Ant-and-Decs prank celebrities. In the newer episode they torment Stephen Mulhern, a light orange TV presenter with just one head. They sabotage his panto. He gets more and more upset, eventually murdering a stagehand out of frustration. Ant-and-Dec reveal themselves, have a good laugh and convince everyone to keep schtum about the killing. I’m exaggerating. Yet I believe Ant-and-Dec could cover up a live-on-air murder if they wished.

Wavy arms

What else can I say? They own a “supercomputer” which in contrast with, say, Google’s servers, has wavy arms that stick out at the sides. Both Ant-and-Decs do what any of us would with a machine of such power – they send it to shopping centres and force strangers to dance for it.

Ant-and-Dec have also cloned themselves in the form of child-replicas Little Ant-and-Dec. And thus a 1,000-year reign is assured. In the newer show Little Ant-and-Dec romp delightfully in the park. On TV3 in the olden days, Little Ant-and-Dec interview a huge, self-satisfied thumb in sunglasses and a black T-shirt. This is Simon Cowell and he peers at them hungrily (his Britain's Got Talent co-judge David Walliams intervenes before he feeds).

And they like musical finales. Contemporary Ant-and-Dec perform a barbershop medley of pop hits but Olden Days Ant-and-Dec's make three enslaved pop bands dance (Blue, Atomic Kitten and all four members of Five) and then nostalgically perform Let's Get Ready to Rumble.

“Watch us wreck the mike!” they sing in joyful mimicry of youthful humanity. “Watch us wreck the mike! Psyche!”

It’s great. It’s also a warning from history.What begins with PJ & Duncan singing about the wilful destruction of audio equipment ends with show trials, celebrity humiliation, fickle games of fate, a tiny clone army, a judgmental supercomputer and boybands in chains.

Indeed, even Ant-and-Dec agree that things have gone too far. “Never again,” they say, as they come to their melodic conclusion. “Never again.”