Cancelled Channel 4 series had one of the darkest scenes in TV history and it's nearly impossible to find

A cancelled Channel 4 series included one of the most disturbing scenes ever aired on TV, and it is now near impossible to find online.

The thriller aired from January 2013 until August 2014, after which the decision was made for it to be cancelled.

Created by Dennis Kelly, the TV series stars Bull's Neil Maskell, as well as Black Mirror's Alexandra Roach, Fool Me Once's Adeel Akhtar and Candyman's Nathan Stewart-Jarrett among others.

It currently boasts a score of 100 percent on Rotten Tomatoes, so it begs the question: Why did it get cancelled in the first place?

The series was cancelled after just two seasons (Channel 4)

The simple answer here is the reason behind many cancellations - low ratings, though the show's many fans were confused as to where they came from.

Nevertheless, Channel 4 viewers got two seasons and 12 episodes of the edge-of-your-seat series, titled Utopia, which centred around conspiracy theories.

It focuses on something called The Utopia Experiments, a graphic novel surrounded by mystery.

When a group of people that met online find a manuscript of the book, their lives take a dark turn as they are pursued by an evil unit called The Network.

They relentlessly hunt the group down, stopping at nothing to keep the book's meaning a secret.

However, one scene from the show, the opening to the third episode of season one, caused a lot of controversy. Check it out here:

Arby (Maskell), an assassin, is sitting in a toilet cubicle when he receives a phone call and then grabs a gun, walking out into a school corridor and shoots a teacher in the head, before heading into a classroom and firing more shots.

As screams can be heard, the agent walks into the hall, running into a boy sitting on a bench, hesitating while pointing his gun at him.

It's a tough watch for anyone, and if that wasn't enough, the character also kills a mother in front of her child at home - grim.

It should come as no surprise then, that the broadcaster received several complaints from viewers about Utopia, while Ofcom reports they received 44 in total for the show, and 37 for this episode alone, according to the Guardian.

The complaints were around brutality, offensive language, and a complaint about child actors being involved in scenes of adult content, while many referenced the school shooting scene.

Utopia is now viewed as an underrated TV series that was cancelled far too soon (Channel 4)

Since it was cancelled in the autumn of 2013, the series has been taken off the Channel 4 streaming platform and is now near impossible to find.

The episode also aired not long after the Sandy Hook Elementary School shooting, where 20 children died, though Channel 4 insisted that 'all material was carefully considered'.

A Channel 4 spokesperson said: "Channel 4 thought very carefully about continuing with the planned broadcast of Utopia.

"The drama is in no way based on real events, and the scenes featuring violence are editorially justified within the context of the storyline.

"All material has been carefully considered in accordance with the Ofcom Broadcasting Code and we were satisfied that, appropriately scheduled in a late night slot at 10pm and preceded by clear on-air warnings about the graphic violence and very strong language, it could be broadcast as planned."