It’s a mark of honour for the British comic book industry that its most instantly recognisable icon is also its most subversive. That achievement is down in great part to Carlos Ezquerra, the Spanish artist who co-created Judge Dredd and died on Monday at the age of 70.

Ezquerra started his career drawing war comics in Barcelona before moving to the UK and working for the anthology 2000AD and others. He brought the iconography of fascist Spain to Dredd’s extremely weird and vivid design and combined it with his experiences of living in Croydon through the 70s and 80s: the punk movement on his doorstep and TV images of policemen charging striking miners.

The eagle motif and helmet were drawn from fascism, the permanently drawn truncheon from police on the picket line, the zips, chains and knee pads from punk. “I was living in Franco’s Spain,” he told an interviewer last year, “but also I was living in Mrs Thatcher’s England.”

Dredd looks like no other comic character before or since. His design makes no practical sense. It has no symmetry or logic to it. No one at the time thought it would work. “Fucking hell,” his co-creator John Wagner said when he first saw the designs. “He looks like a Spanish pirate.” But somehow, for reasons no one can quite articulate, it is perfect.

Ezquerra’s art exploded off the page. It was dynamic and gritty, and yet always unfussy, practical and full of economic storytelling. His thick slabs of ridged inks and expressive characters are embedded in the brains of countless readers.

He created strange and twisted worlds and inserted them into comic magazines whose sci-fi dressing made them seem relatively innocent at the newsagent. Thousands of unsuspecting parents were conned by this bait-and-switch into buying their children transgressive anti-authoritarian parables and punk-inflected satire without knowing it.

‘Carlos Ezquerra brought the iconography of fascist Spain to Dredd’s extremely weird and vivid design and combined it with his experiences of living in Croydon through the 70s and 80s.’ Photograph: Michele Brittany

The oddity of the costume, and the design emphasis on fascist chic, pushed Dredd into strange storytelling territory. In some stories he was the hero, in some the villain. Very often, he wasn’t the protagonist at all. The genre switched from sci-fi action to horror or comedy, from police procedural to scathing political commentary.

Ezquerra was an absolute workhorse, drawing countless stories for 2000AD until just weeks before his death. He never declined artistically. As he entered his eighth decade, his work was still a riot of grim flamboyance.

Over nearly 40 years he drew some of the lawman’s most indelible moments. But one in particular, during a storyline called The Apocalypse War in 1982, is seared into the memory of everyone who read it.

Dredd has sneaked into a Soviet military command centre and secured the opportunity to launch a revenge nuclear attack. “Please, Dredd – don’t do it!” an enemy pleads. “There are half a billion people in my city – half a billion human beings! You can’t just wipe them out with the push of a button!”

“Half my city is burnt to ash … and you’re begging me for mercy?” Dredd replies. “Request denied!” And then he presses the button and kills half a billion people.

Anyone who read that scene as a child can visualise it instantly in all its detail, even now: Ezquerra’s unmistakable linework, the decision not to draw Dredd in an action pose but simply standing there, unhurried and unaffected, even the motion lines on his finger as it hit the button.

His art was so vivid that it brought these key moments to life. But more than that, Ezquerra’s design created the preconditions for a character who could operate outside the bounds of genre or storytelling tradition.

This scene, which took the action protagonist and turned him into a mass murderer, perfectly distilled 2000AD’s subversive instincts. It was a complete rejection of the culture of American comics, which always encouraged readers to put their trust and faith in the superhero. Instead, this was the message: never trust figures of authority.

Even now, when you talk to fans of Dredd, they will often cite it as a crucial part of their political development. Ezquerra’s work inserted a rebel instinct in his young readers. This was his revenge against Franco’s Spain and Thatcher’s England.

• Ian Dunt is the editor of politics.co.uk