“Miss, do you have Instagram? Do you have Snapchat?”

“Yeah Miss, can we see your Snapchat?”

A group of 13-year-olds — all Year 9 students at the Lilian Baylis School in Kennington, south London — come buzzing to my iPhone like a swarm of bees to a briefly exposed honeypot. Before I can react, they’ve already got their hands on it. My Snapchat is open.

“You got bare adds though. You’ve got nine adds. Do you know these people?”

“Miss hasn’t even added them back! Show me! Show me!”

“If you don’t know them, don’t add them. Unless they’re friends of friends. That’s OK. But never someone random,” advises one girl, Kushana, solemnly.

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“You’ve screenshotted a Snap. You screenshot Snaps?” says another student, Oumar, eyeing me with faint disdain. “Your Snap score is 500 though. That’s good. Look, you’ve got loads of people to talk to.”

When they hand my phone back, I discover Snaps they’ve taken of one another, with special filters and lenses: one of a strangely angelic-looking Kushana and her friend Jada-Renee, wearing crowns of pink flowers atop their plaits; another of Kylie, posing moodily with fluorescent flowers floating above her head.

“We’re Snapchatting in our uniforms, but you’re not gonna post it, are you Miss?” Kylie asks anxiously. This isn’t a school rule, but the kids know their uniforms can be easily identified by strangers online. Then, appraising me and instantly changing her mind: “But you can if you want. It will disappear after 24 hours so don’t forget to save it to your memories.” She helpfully grabs my phone and shows me how.

While these 13-year-olds educate me on the perils of Snapchat, adults are worrying constantly about how screens are moulding young brains. We are all fixated on the idea that growing up in a digitally connected age is fundamentally different from childhood in previous generations, a change shaped entirely by the internet.

Researchers are busy analysing every aspect of the web’s effects on kids’ social behaviours, mental health and even physiological development. There are papers on new types of bullying, from revenge porn to trolling, and studies assessing the rise of cyber-savvy paedophiles and criminals. Everywhere you turn, grown-ups are volubly voicing their anxieties about the smartphone generation.

But what about the children themselves? They’re the real denizens of the virtual world — the super-users of new apps, the earliest adopters of new forms of social media, the connoisseurs of online entertainment and the harshest critics when these technologies don’t meet their standards. And yet the wave of parental concern often drowns their voices.

So I set out to hear their perspective directly — what they like and don’t like about phones, what apps they use most and why, and how their real selves are tied to online avatars. What I discovered along the way — in classrooms, playgrounds, cafés and online — was always entertaining and often unexpected.

One of the many concerns voiced about the phone-wielding social-media generation is that children are becoming increasingly isolated — spending more and more time staring at screens in their bedrooms rather than engaging in face-to-face interactions. Back at Lilian Baylis, I’m trying to understand what friendship means at a time where most kids have hundreds of online “friends” and followers over a variety of channels.

Kylie, a second-generation Ecuadorean, lives in Brixton with her sister and parents; she is best friends with Cheydna, who is Angolan-Portuguese and lives with her mum and older sister just a few minutes away from school.

What does being best friends involve, I ask the girls. “Basically, it means we FaceTime every day after school. I don’t like other people seeing me outside of school, because I look different in a school uniform than my own clothes, I look older. So I only FaceTime her,” Kylie says.

“She keeps all my secrets and we speak to each other in Spanish and Portuguese, which no one else understands, so it’s cool,” Cheydna adds.

“We both want to be criminal lawyers. So we FaceTime and focus on our education; we do our homework together,” Kylie says.

How would the students feel about life without their phones?

“Me and my phone, we are best friends, I’m closer to my phone than family. It’s the first thing I look at in the morning, and the last thing at night,” Kushana says.

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“To be honest, I isolate myself when I’m at home. I’m always on my phone when I’m [there]. It’s not always because I’m talking to someone, I just don’t feel right without it,” Kylie pipes up. “So I hang out on the couch with my phone and my headphones. I don’t mind talking to real people as long as I have my phone next to me.”

Social psychologist Sonia Livingstone spent a year observing the lives of 30 children aged 13-14 in London for her book The Class (2016). One thing that struck her was how social media was more than an alternative form of communication — it was an entirely new space for young people to assert their identity.

“The internet allows flexibility and experimentation, so if you’re the Somali kid or the one who loves chess, or who is gender-fluid, you can meet others like you, even if you spend most of your time in a five-mile radius of school or home,” says Livingstone, a professor at the London School of Economics. “Until the last decade, it was very hard to find or get recognition for any niche identity as a child, but that’s a key feature of the internet. It’s extraordinary.”

Take George, a supremely cool 14-year-old from a private girls’ school in Marylebone, London, with casually windswept, cropped black hair, checked shirt and jeans and a cracked champagne gold iPhone 6. In a few weeks, the cropped black hair will turn spiky pink. George was born a girl, and christened with an “embarrassingly female” name that isn’t used any more.

“It was Year 8 and it just occurred to me, I was just like, ‘OK, I think I’m bisexual — oh wait no, I’m pansexual’. Then I read more and decided I’m gender-fluid. I’ll feel more masculine one day and more feminine another day. I’ll generally dress neutrally and I use ‘they’ or ‘them’ pronouns, which is actually really hard at school because teachers will just call you ‘she.'” Now George just goes by George online, which is what really matters.

On Instagram, a plethora of LGBTQ communities helped George figure out “their” identity as a 12-year-old, by speaking to others who were having similar thoughts, or those who had recently gone through a transition. “A lot of the LGBTQ community is on Instagram. We were on there at 12 and 13, with little butterflies, with the pansexual pride flag and that kind of thing, and Instagram was the way I found out about it.”

Political discussions are mostly restricted to Tumblr and Twitter. The London teen identifies with the Liberal Democrats. “They have things like votes for 16-year-olds, they were big with the same-sex marriage bill and that’s what I really cared about. Tumblr is free-range, it doesn’t filter, which is interesting politically, because you’ll have the furthest left people and the furthest right people and you’ll be able to look through both of their blogs.”

“They do seem a confident generation, don’t they?” laughs Livingstone. “Walking home from school or in their rooms at night, when they have escaped the teacher and aren’t under the control of their parents, that’s where they go on to digital platforms and try things out with friends, hang out and experiment, and be independent.”

To Sacha Cuddy, 18, Instagram is saving her life. The dark-haired, pale-skinned teen has large eyes and a delicate silver ring piercing her nasal septum. She’s just recently gone back to finish college in Lancashire. This is her first summer at home after two spent in hospital. I know all this just from her Instagram account, where she has 16,500 followers and posts at least once a day. On Instagram, she describes herself as a writer and an “anorexia fighter and survivor”.

I had almost given up getting her to reply to my emails, but then try her on Instagram, where her responses are instant. “Words are incredible, but adding a visual to your words is even more moving,” she DMs [direct messages] me. “I picture my posts like lyrics in a music video. It’s beautiful and tells more of a story.”

When she was 15, Sacha went on a diet that turned into three years in which she lived on only 5-10 per cent of her recommended daily intake. “I ended up in hospital twice. And I almost died a few times due to health complications,” she writes to me. “I stopped doing anything I loved when I became ill. But one day, I took a photo of myself and took a step back. I thought, ‘So what is actually wrong with my body?'” She wrote her first Instagram post about that photo, and since then her account has exploded with comments of support and conversations about body acceptance, self-harm and mental health.

Now, she says, her Instagram community is one of her biggest inspirations to get well. “Sadly, there is always a pressure to be someone you’re not [online] and I’m trying to fight that,” she tells me. “My whole message is that you DON’T have to look a certain way.” Scrolling through her selfies and motivational posts reveals raw comments from other teens. One writes: “Your posts have honestly helped me so much. I’ve been going through so-so much lately and for the first time in six years I’m finally starting to see an end to all my pain and see myself becoming happier again.”

“[Social media] has made people my age feel more open about what they can share,” Sacha says. “I feel my generation is more compassionate and open-minded.”

With no legal age requirement for smartphone use, it’s up to parents to figure out the right time to induct their kids. A study from research firm Influence Central last May found that the average age children receive their first smartphone is now 10.3 years old.

That seems consistent with the kids at Bishop Gilpin in Wimbledon, south-west London, where I’m talking to a class of excitable 10- and 11-year-olds. They’ve been asked to take selfies in the playground later for the FT, so everyone’s busy planning what theirs will look like.

Still too young for social media platforms like Snapchat and Instagram (which require users to be 13 or over), most have just started owning smartphones, although pretty much everyone had an iPad by the time they turned eight.

Many parents are concerned about the effects of screen time on children this young, and all the kids I speak to have a device curfew at home, usually before they go to bed. “If I do something bad they ground me from devices, so I tend to be good when they are watching,” says Max, 10.

Unlike the teenagers at Lilian Baylis, the 10-year-olds I spoke to were uninterested in social networking on their phones. Mostly they played games and watched silly videos, although some were starting to display early signs of the addictive attachment that the 13- to 14-year-olds showed towards their devices.

“On my iPad I have Minecraft and Clash Royale [a hugely popular mobile game in which players battle to destroy enemies’ forts and castles], plus I like games like Subway Surf and Color Switch,” one 10-year-old boy tells me.

“I watch people playing Clash Royale on YouTube,” says Jack, a slight 10-year-old with a sweep of dark hair, who has recently moved here from France. “I also have my own YouTube channel, and when people put comments where they insult me, I just ignore them most of the time. My dad told me to do that.” What does he film himself doing on his YouTube channel, I ask? “Clash Royale”, he replies.

“I watch ‘Try Not to Laugh’ videos, where people do funny things and you have to try not to laugh. Like that one when a massive tower of Jenga falls on a guy’s face. Or that one where the baby runs away from its grandma,” another boy says, giggling.

“Sometimes some of my apps, if I ever get nervous, they help me calm down,” says Ariana shyly. “I like the game Cooking Fever, where you basically have many restaurants and you have to cook and collect as much money as you can.”

“And slime videos on YouTube, they’re fun,” says Layla. “You just find stuff around the house, so you go through the recycling bin and take stuff out. They give you ideas on YouTube for what you can use around the house to make slime.”

“I literally love slime,” says Jack.

Would they prefer to spend time online than in the real world? “I kind of like it,” Max tells me, “but I get annoyed when older members of my family, like siblings, when they’re at the table, they start looking at their phone and I’m trying to talk to them. Sometimes it gets frustrating.”

“I always tell my mum to get off it,” another child says, rolling his eyes. “Every time she wakes up, the first thing she does is Facebook. I try to remind her you’re supposed to make breakfast, or you’ve got a job to do, but she’s just staring into her phone.”

So when do they use their devices most, I ask? “When I’m not ready to go to bed,” Misha tells me. “Let’s say, I’ve just got bad dreams or I can’t go to sleep. I just turn on the iPad and research something. I would rather be watching, let’s say, movies or YouTube.”

He continues: “Sometimes one of the best apps to use is where you don’t need your email or to get online. When you’re tired and in bed, you can just play Roblox for 10 minutes and it makes you relaxed. And if your parents come along, you just hide it under the bedsheets.”

To the adult mind, all apps are bunched together under the giant, amorphous label of “social media”. Social media has encouraged smartphone addiction, worsened impulse control and upped the consumption of pornography, according to a range of studies. A recent report from the Royal Society for Public Health discovered that anxiety and depression are exacerbated by heavy use of social media apps such as Instagram, Snapchat and Twitter.

But for the children I spoke to, each platform is distinct, in the same way that previous generations would see a telephone and a television as different. George, for instance, has just six carefully chosen friends but they speak all the time, through multiple channels. On Instagram, George has four separate accounts — one for LGBTQ activism, another for singing, a couples’ account run with a girlfriend and then a personal one.

On Tumblr, every morning and every evening, George and a friend write an episodic fictional tale together, by texting character dialogue back and forth. Someday, they want to publish the transcript. On YouTube, George’s most watched channels include the satirical series “jacksfilms” (with 3.3 million subscribers), “TheRPGMinx”, which features gaming videos uploaded by a lesbian gamer couple (nearly 300 million views) and “How to Cake It”, a quirky baking channel (3.3 million subscribers).

On George’s neatly organised phone home screen, WhatsApp, Twitter, Snapchat, Spotify and Google Docs occupy prime real estate.

Swipe left and you find a smattering of less-used apps including Pinterest, WattPad, Ever and YouNow. Each app has its own personality: Tumblr is creative, Instagram is personal, WhatsApp is for group chat, Snapchat for conversations, Twitter for news and Google Docs is for homework. There is one much-neglected Facebook account which is “so weird, it’s just my mum’s friends that follow me”. Most accounts don’t use George’s surname; many are operated under fake names for privacy. For younger teens, Snapchat rules.

“When I can’t go on Snapchat I cry. Like actually,” Kushana from Lilian Baylis says, shaking her head in horror. “I still use Musical.ly sometimes,” she adds, referring to a recently popular app that lets kids lip-sync to famous songs.

“Yeah, we used it more when we were in Year 7, before that it was all about WhatsApp groups, remember?” Kylie says.

“I talk to random people on Snapchat, but I add them before deciding to block them or not. To see if they’re actually interesting,” Oumar, another student, tells me.

“You talk to strangers on Snapchat? You know it could be a 40-year-old paedo man in Essex?” Nusaybah demands.

“I don’t post stuff to them; I just see what they post and then I watch to see who they are and add if I like their stories,” Oumar says defensively.

“This guy snapped me the other day, saying, ‘I know you, I see you on the bus every day.’ Creepy,” Kylie says.

For Harsita Raja, 17, from north-west London, Snapchat is where “I actually interact with people. It’s a daily thing. If I’m having a proper convo it can be around 50 a day with a single person,” she says to me (via Snapchat).

On Instagram, she follows all her friends on “finsta” accounts — separate accounts that they operate as private groups, where you can post personal or funny things that you wouldn’t put on your regular Instagram because it’s too public. Harsita’s finsta has about 100 people on it. “Just for safety, I guess, and I don’t really like the fact that anyone can look at what I was doing at a given time,” she tells me.

Researchers have found that social media use — particularly photo-driven apps — is intrinsically tied to self-worth in today’s teens. “There’s a particularly pernicious aspect on social media which is about presenting your best self, like pictures of you in the best light to look super-skinny,” says Adriana Manago, a social psychologist at the University of California, Santa Cruz, who specialises in youth development and technology. “But it’s not an accurate representation of people’s lives, and it can amplify insecurities in the most vulnerable kids.”

Does Harsita agree? “Unfortunately, yes.” Everybody compares the number of likes and shares they get, and no one likes to come up short, she adds. “The bigger the better. The number is just an instant gratification. For FB or Insta it’s usually over 200 likes. [The feeling] is like disappointment. Sad, but there’s no denying.”

Because the digital realm is largely unchaperoned, invisible and unintelligible to many adults, kids call the shots. In 2015, Ofcom found that 12- to 15-year-olds were spending twice as much time online as they did 10 years ago. A YouGov survey found that more than half of British children have access to the web in their bedrooms, without adult supervision.

Allison Havey, co-founder of The Rap Project, which helps raise awareness about issues such as intimacy, relationships, porn and sex among British schoolchildren navigating an online world, can already see a difference between generations.

“I have a very open relationship with my daughter about life online. But I missed the boat with [my 20-year-old son] Mike, because we didn’t have that dialogue. But I learnt from my mistake and started that conversation with Isabel [15] at 10,” she says. “She doesn’t show me everything, of course. Her group is into fashion and make-up. She loves to buy, sell and try clothes online; she’s a big fan of [online marketplace] Depop.”

A few months ago, Havey’s daughter was trying to sell a pair of shoes on Depop and was approached by a buyer; as the communication continued, the buyer demanded more photos of the shoes being worn by the 15-year-old; when they asked her to send a video of her applying foot lotion before she put the heels on, Havey realised her daughter had become the unwitting victim of a possible foot fetishist. “If a middle-aged man came up to you and asked, ‘What’s your favourite music?’ and then, ‘What do you look like in a bathing suit?’, you’d say ‘eww’. But online that guard is dropped,” she says.

Havey often shares the biggest lesson she’s learnt from her own kids with other parents. “Ask your kids, ‘Which friend has the most interesting Instagram posts, why, can you show me? Who is really funny on WhatsApp? Who’s weird? Who do you like watching on YouTube?'” she says. “If you start asking them at 11 and 12, they’re more likely to include you as they grow older.”

For those concerned about the well-documented addictive nature of smartphones, some research suggests that many children are slowly starting to emerge from the haze, with some even experimenting with a tech-lite lifestyle, especially as they get past the hump of their early teens. In May, a survey from the social research organisation NORC at the University of Chicago found that 58 per cent of American teens reported taking breaks from social media, many voluntarily.

Sanjana Poddar, 15, from Wimbledon, says she outgrew Snapchat earlier this year. “It just got annoying because it was constantly everyone documenting everything. After a point I didn’t want to be in a room of people where everyone was staring at their phones,” she tells me. Sometimes, she does feel like she’s being excluded or missing out when everyone at school is sharing funny Snapchat stories but then she remembers why she stopped. “It was like forcing someone to remember you existed. And I got tired of it.”

She still uses WhatsApp for group chats, Instagram to look at art and Spotify. On Twitter, she follows writers and politicians such as Donald Trump, who is “quite amusing and keeps me updated”, she says. But when she wants to really focus, she uses an app called Forest. Set a timer for as long as you want — say, 30 minutes — and a virtual garden begins to grow on your screen. If you use your phone, “your virtual trees will die and your garden looks ugly. It’s a really cool app.”

She knows she will never give up the internet completely. “It does define our generation for a large part. We know how to use it and we use it the most. But I do think that it is making people lose touch; people are so used to the protective barrier of using electronics that when it’s gone, they feel insecure,” she says. “Social media does allow people to be themselves, I guess, but you can’t just live online, can you?”