After a wait more interminable than most spells in an A&E reception area, medical-drama-of-the-moment The Pitt finally made it on to UK screens last month, via the arrival of streaming service HBO Max, and just about everyone I know has spent the following weeks hoovering it up. Some, in fact, are already up to speed with its second season (the finale aired last night on US TV) and so are trying very, very hard not to blurt out major plot points at the office tea point/on public transport/in an actual hospital waiting room – we’re in a post-spoiler age, remember.

I’ve been a little bit slower off the mark – mainly because it took so long to figure out if I actually had access to HBO Max as part of my bafflingly arcane Sky TV package – but I’m racing through it now, and so am ready to share the same observations that everyone else made weeks, or in the case of the US, a full year ago. The main one being: how did not one TV producer have the idea to mash together ER and 24 before? It was right there, staring you all in the face! (Jed Mercurio, whose forgotten 2015 medical drama, Critical, also had a real-time element, might have a finger raised in objection at this point.)

Beyond The Pitt’s formal innovation (each season follows, to the second, a 15-hour shift at an under-resourced teaching hospital in Pittsburgh), what’s striking is how familiar it feels. In part that is down to the comforting presence of Noah Wyle, who as the show’s lead – big-hearted, sad-eyed senior attending physician Dr Michael “Robby” Robinavitch – is essentially playing a continuation of his ER character John Carter, a fumbling junior MD who became the show’s inspirational figurehead. But the familiarity doesn’t begin and end with Wyle: it’s there in the show’s very foundations. With its jarring tonal shifts between soft relationship drama and intense, claret-spilling operation scenes, The Pitt plonks itself unapologetically in the lineage of the modern medical drama, a strange stew of comfort TV and high-tension unpleasantness that viewers seem to find endlessly appealing.

In the UK and the US, early medical dramas were often soap operas, a genre that tends to prioritise formula and a sense of the familiar over formal daring. (Which isn’t to say that they were conservative – one of the first interracial kisses on British TV occurred on the ITV soap Emergency Ward 10.) But in the 1980s the medical drama started to evolve, on both sides of the Atlantic. In the US there was the arrival of a new generation of gritty, layered workplace dramas, including the hospital-set series St Elsewhere, now remembered largely for its completely crackers ending, but revolutionary in its use of multi-strand plot lines and of-the-moment subject matter – among other landmarks, it was the first show to feature an Aids storyline.

Meanwhile in the UK, the BBC launched Casualty in 1986, a show that might feel hopelessly traditional to viewers today, but was anything but when it debuted. Conceived by its creators Paul Unwin and Jeremy Brock as an unflinching look at how Thatcherite reforms were destroying the original vision of the NHS – “In 1948, a dream was born. In 1985, that dream is in tatters” read the first line of a manifesto the pair wrote for the show – Casualty prompted hoots of complaint from the Conservative government of the time. (“What do the Tories want us to do? Make the blood blue rather than red?” was controller of BBC1 Michael Grade’s response.) The show rarely seemed to be out of the headlines in its first decade: most famously, a 1993 episode where a gang of violent youths burned down the hospital had to be moved past the watershed and received record complaints due to its violent scenes.

At around the same time, ER emerged in the US and changed everything, a blockbuster medical drama that fully modernised the genre. Its storylines – opioid addiction, mental health crises, institutional racism – were remarkably bold for its era. And with its heightened commitment to medical accuracy, verité filming style, sprawling casts, sudden tonal shifts and so much more besides, it set the template for every similarly minded shows that followed. As well as long-forgotten straightforward knock-offs including Code Black, Chicago Med and The Resident, you can see ER’s influence in everything from the gentler likes of Grey’s Anatomy and the Good Doctor, to pricklier takes on the format such as House (pictured above).

And of course The Pitt, a show that was reportedly conceived as an ER reboot and is now subject to a lawsuit from ER creator Michael Crichton’s estate. So why has it chimed with viewers when so many other ER-a-likes have been memory-holed? Much of its success is down to that conceit where minor storylines from early episodes spiral off into something unexpected and major, turning the medical drama’s procedural format into something satisfyingly elongated. But The Pitt also has the same nettle-grasping spirit as the landmark medical dramas. It is unafraid to take on live issues – ICE agents descending on hospitals, post-Roe-repeal abortion restrictions – and unwilling, like Casualty with the NHS, to gloss over the risible state of US healthcare, as one grim storyline showing the ramifications of a patient’s insulin rationing shows.

So perhaps my year-late observation is actually this: The Pitt is a show that captures the medical drama at its best, and leaves the genre is safe hands.

To read the complete version of this newsletter please subscribe to receive The Guide in your inbox every Friday