It is, from afar at least, something out of a JG Ballard novel. Those three towers prickling the sky like great concrete Stickle Bricks must have something dark going on inside. Watch one long enough, and you'll surely see a moustachioed man plunging from one of the curved balconies, slo-mo, into the bonnet of a Ford Cortina.
That stern 'Barbican' name matches the design; its architects Chamberlin, Powell and Bon essentially built a 20th century armoured fort for City workers to rent during the week. Arrowslits peek into an underground car park, one of many architectural nods to the area's previous life as a stronghold.
But inside the estate walls, at 10am on a Sunday, the scene couldn't be more soft centred. Sarah and Tim are sprawled out on the carpet, playing with their young son, Joseph. The windows in these lower flats in Andrewes House span the width of the rooms; it's light, fluffy and spacious.
It's all so peaceful; no traffic outside, little other noise aside from the fountains plinking on the lake. OK, the City's quiet on a Sunday as a rule, but inside the Barbican it's always like this. The strong residents association doesn't bite its lip when it comes to noise pollution; the online residents forum is essentially somewhere to sound off about noise.
"My dad was managing director of the LSO So I spent a lot of time at the Barbican growing up," says Sarah. "Partly because mum and dad weren't keen on the architecture, I grew up thinking it was just rather ugly and hard to find your way around."
Those perceptions gradually mellowed, and when she and Tim had to vacate their place in Islington, a friend mooted Barbican. "We thought we'd just move here for six months," says Sarah, "and that was three and a half years ago.
"The thing that makes me laugh is that we moved here thinking 'before we have children or anything like that, let's do something really fun and grown up. We'll go and live in the Barbican — cultural hub, lots of cinema and things...'
"And we've sort of used that. But actually it's properly come into its own now we've got a little one."
Any toddler will eye up the Barbican and its puzzle of walkways as one big playground. There are endless avenues to explore inside and out. Sarah and Tim know about 25 young families around the estate. The Barbican Centre lays on a feast of family friendly events too; Tim took Joseph to The Gulch at least once a week for the duration of its run. The Barbican has actual playgrounds too, should any child need it.
So much for Ballardian dystopia, then. But to those already itching with envy, Tim and Sarah do admit to the odd idiosyncratic niggle. While the concrete between the flats' floors means you don't get the sound of your upstairs neighbour bounding over your head, it does carry the sound of a drill bit for blocks at a time.
Bigger power tools are on the horizon; the Barbican's 6,500 residents make up more than half the population of the City of London, but that's changing, as people move back into the business district. For the first time in its history, high-rises are beginning to peek over the Barbican's battlement. "The Barbican under siege," quips Tim. It's weird to think of this great brutalist clod having its identity threatened by high-rises.
Meanwhile, a gentle envy bristles among Barbican's residents; they covet each other's flats. Once you've staked a claim, explains Sarah, it's pretty standard to move up rungs within the estate. You can understand the temptation, given that your dream home is there when you open the curtains each morning.
Tim and Sarah have already lived in Speed House, and now have their eyes on a third, bigger, lighter Barbican flat (there are 141 varieties of these — the architects tweaked as they went along). Is the couple's grand plan to be in one of the three iconic towers — Cromwell, Lauderdale and Shakespeare? "I wouldn't want to live right at the top," says Tim. "It's more of a human scale down here," adds Sarah.
Those towers do have their perks; the views across central London (the Barbican once had the highest residential towers in the city) are one thing, and there's a concierge service too. It's probably swisher than living in The Shard.
For the moment, Sarah and Tim are happy with their current place. "I love the way the kitchen and the living room intersect," says Sarah, "for living your life as a family, being able to cook in here and passing things through, and paying attention but also being a little closed off, it's great design."
Tim shows us a little cupboard next to the front door. They place rubbish and recycling bags in here, which is emptied from the outside every day. A sliding wall means that when Joseph came along, they could essentially cleave the living room in two, and create a second bedroom.
The estate also has a holding room, where Barbican staff take care of everything from parcels to sofas."Everywhere should be set up like this," says Tim, "in a city, especially days where you work more and you've got a way more hectic life... living in the Barbican makes our lives so much easier." It must at times be like living inside one of those twee promotional 1960s videos with a slick voiceover.
Indeed, living in the Barbican, you do more than grow to accept it; you understand it, fall in love with it, more and more each day. "When it's a beautiful sunny day, you see stunning silhouettes around the estate," says Tim, "you'll see designs being repeated in lots of completely different places."
Pointing out the living room's mid-century lamps and prints, Tim explains he hadn't been into this kind of aesthetic before moving here. Now, the Barbican's influence runs through his veins like unset concrete.
Of all the estate's perks, maybe the best is the 'magic key.' The Barbican's enough of a maze as it is, and to find some of its doors and gateways locked is an added frustration to any visitor. The key, awarded to each of the 2,000 flats, is the equivalent of levelling up on a platform game. It takes you underneath brutalist waterfalls, onto juicy swathes of lawn. In spring the flower boxes explode with red geraniums, and in the private gardens, you find yourself surrounded by this. There's even a competition for the best display, as if in some small village. The Barbican isn't just brutalism, it's bucolic brutalism.
People still guffaw at the post-war optimism of the Barbican, otherwise tutting at the 'poor sods' who've found themselves living on such a ghastly estate. True, it didn't all take off; the pedways were deemed a failure. But so many of the 1960s touches are still paying off half a century on. London can build all the 'conveniently located' luxury apartments it wants; it won't ever get another Barbican.