One of the most memorable moments in Jimmy McGovern’s new drama, Reg, comes halfway through. Reg Keys, played by Tim Roth, stands outside Downing Street and demands that Tony Blair come to the door. Keys wants to talk to the prime minister about the soldiers who have died in Iraq. Blair’s flunky refuses, saying he is simply too busy right now.

“People who’ve given a few grand to the party, they get to see him,” says Keys, quietly furious. “Well, we’ve given a lot more than that – we’ve given our sons.” It’s a very McGovern moment, filled with a righteous rage at how the establishment can treat ordinary people.

Anger is essential to TV. And Reg, which airs on BBC1 tonight, thrums with fury, despair and disbelief. McGovern and his co-writer Robert Pugh use the story of the retired paramedic, first broken and then galvanised by the death of his serviceman son Tom, a lance corporal killed by an Iraqi mob in Majar al-Kabir in 2003, to examine grief and betrayal of all kinds.

We see Keys move from devastated by Tom’s death to furious at the lies he felt Blair was telling about the war. We watch him become increasingly political, until eventually he decides to run against Blair in his own constituency of Sedgefield.

But McGovern is intent on telling the whole story. So we see Reg, going door-to-door campaigning in Sedgefield, realising that some people believe his son deserved to die – and that others lambast the whole war. “Your son chose to fight, Mr Keys,” says one outraged constituent. “What about the Iraqis? You’ll understand if I don’t share your pain.”

Most powerful of all are the moments involving Anna Maxwell Martin as Reg’s wife Sally, poleaxed and struggling to comprehend how and why her family has been torn apart. It is a sombre drama, and an emotional one, but the thing that makes it stand out is its anger.

Carol White and Ray Brooks in Cathy Come Home, 1965. Photograph: BBC

Britain’s best television has always been its angriest, from Cathy Come Home, which put homelessness in the spotlight, to Scum, Alan Clarke’s incendiary look at life in borstal. These are the shows that force us to think about things we might otherwise have ignored, that hold up a mirror to society and say: ‘This is what you got wrong, this is where you failed.’ We might not always agree with the writer’s point of view but, at its best, their anger jolts us. It makes us consider television as more than just the comforting gogglebox; it makes the case for TV as art.

Sometimes, it can seem as though we’ve forgotten that. As though we prefer our TV with a solid dose of comfort, retreating into cosy costume dramas and vegging out in front of endless talent shows.

In such a climate, Reg seems almost a throwback to the 80s, a decade full of furious, issue-led television. From Alan Bleasdale’s bleakly funny call-to-arms, Boys from the Blackstuff, to his indictment of local politics and careerism, GBH; from the dark humour of A Very British Coup to the paranoia of Edge of Darkness. Even ostensible comedies such as The Ritz, John Godber’s story of three bouncers in a rundown club, hummed with an anger about communities destroyed and lives put on hold.

That might have been the golden age for issue-led TV, but it hasn’t entirely disappeared. In the late 90s, Leigh Jackson’s brutal and brilliant Warriors, directed by Peter Kosminsky, turned a cold and angry eye on events in the Balkans, telling an unsettling story of British peacekeeping troops in Bosnia. More recently, Jed Mercurio’s dramas stand out because he is genuinely angry at how institutions can fail people. His first series, the hospital-set Cardiac Arrest, was driven by a real rage at the way overworked junior doctors were being let down. Next up was the furious Bodies, which riffed off controversies such as the Alder Hey organs scandal to tell a tale of institutional incompetence and an NHS throttled by red tape and sinking in a morass of mismanagement. Mercurio’s most recent drama, the police thriller Line of Duty, put its cards on the table when Adrian Dunbar’s Ted Hastings (probably the show’s one truly honest man) laid into Operation Yewtree with a searing speech. “How much money are we going to spend chasing clapped-out DJs?” he demanded, before concluding that the truly guilty could hide their sins behind job titles and the power their institutions give them.

Boys from the Blackstuff. Photograph: BBC

Angry TV can also be seen in the intimate stories of This Is England, the creeping dread of Happy Valley and in the heavily stylised Peaky Blinders, which pulses with Tommy Shelby’s fury at being an outsider in an establishment world. All these shows are more than pure entertainment: they are dramas that ask wider questions of their audience. You may not agree with Steven Knight’s class commentary, Sally Wainwright’s dissection of the nature of vengeance or Shane Meadows’s bleak indictment of post-Thatcherite life, but all three programmes are smart and sharp – and all three are furious.

The important of rage to television drama was further highlighted by ITV’s decision to rescreen McGovern’s 1996 drama Hillsborough in the wake of the recent verdict. Like Reg, it is a powerful look at a real-life story underpinned by an anger at the lies told to the families of the 96 who died. The passing of 20 years has not dimmed its power – if anything, the catalogue of injustices outlined in the inquest only reinforces how right McGovern’s fury was all those years ago.

Does that mean television should only be angry? Of course not – the medium thrives on variety. It should be full of smart comedies, pure moments of escapism, and soaps and procedurals that you can relax into, like hanging out with old friends. But the best of it … the best will always have a splinter of ice-cold fury at its core.

Reg is on BBC1 at 9pm tonight.