Sending and receiving explicit naked pictures is everyday life for teenagers aged between 13-16 across Britain - and it is changing how they see sex, a Channel 4 News investigation reveals.

Warning - this video contains use of explicit language.

Please wait while this video loads. If it doesn't load after a few seconds you may need to have Adobe Flash installed.

Warning: This report contains sexually explicit material.

"I get asked for naked pictures...at least two or three times a week."

"You would have seen a girl's breasts before you've seen their face."

These are the words of a 15-year-old girl and boy sharing their experience of growing up in 21st century Britain. They are talking about sexting - the sending of naked photos on mobile phones. Whilst you might think this behaviour is at the extremes, this is in fact becoming everyday life.

For six months, Channel 4 News and the NSPCC have been speaking to children aged 13-16 up and down the country to find out what the average young teenager in the average school faces on a daily basis. Previous research has focused on inner city schools but we have spoken to over 200 kids across nine English counties about what teenage life is like. And what we found is hard reading for parents.

I get asked for naked pictures...at least two or three times a week. One 15-year-old girl

One 14-year-old girl in Berkshire told us about the messages she has been sent asking her to reply with a smiley face if she wants sex or a wink face if she would give the sender oral sex. Unsurprisingly, technology is at the core of interactions and with smart phones in almost every child's pocket, the sending of naked images is the new currency. It has become so commonplace the children refer to them simply as pictures and sometimes the requests come from boys they do not even know. To coax the girls into responding, boys will send unsolicited pictures of their genitals.

Sexual revolution

When Philip Larkin declared that sex began in 1963, Britain was in the grip of a sexual revolution in part enabled by the introduction of the contraceptive pill. But when you listen to the grandchildren of that era talk about sex today, it makes the swinging 60s seem naive. Back then, porn was the occasional dirty magazine passed around the school, a time when childhood slowly evolved into adolescence. Today, there are new rules of the playground.

Read more on Generation sex: finding out the new rules of the playground

One 15-year-old girl told us: "Before, everyone - like my dad - the first thing he'd ask a girl, 'Could I give you a kiss?', but now it's kind of - do you want to have sex, would you give me a blow job?"

Professor Andy Phippen from Plymouth University carried out the research for the NSPCC. He told Channel 4 News: "That's the significant thing, it's really starting to show that this is mainstream, this is normal, this is almost mundane for some of the people we spoke to. In pretty much every school in the country, people aged 13-14 are talking about this stuff and dealing with this stuff."

'Sexting' is just part of life, teenagers tell Channel 4 News (Getty)

Jon Brown from the NSPCC told Channel 4 News that they thought it important to do this research to get an insight into young people's views on sex.

"What we're seeing is that there is a very regular and normal consumption of hardcore adult pornography - that the sharing of explicit sexual imagery by photos or by video clips is now extremely normal, so I think it's important to recognise what was previous regarded as unusual, concerning, or sensationalist, now has in fact become the norm," he said.

The research reveals that the whole nature of relationships is changing. In speaking to teenage boys and girls, Andy Phippen found that they were deciding whether or not to begin a relationship dependent on what images the other person would send them. Girls we spoke to referred to sexting as the new flirting and have come accustomed to being asked time and again for pictures.

Brave new digital world?

To the young people involved, this brave new digital world is not as scary as it may sound. One 15-year-old boy told us: "It might shock parents that like this is what kids get up to but to them it's just everyday life, it's natural, all part of growing up."

But whilst they appear to be robust, they are also feeling the pressure. A 15-year-old girl told us that boys expect girls to have shaved their pubic hair because that is what they are used to seeing in porn. And whilst boys are often seen as the perpetrators, they tell us it is not easy for them either. One 15-year-old boy said they feel "put under pressure to get these photos of girls, to have muscles, to look this certain way, to be able to, like, do all these positions and be able to last the longest in bed."

It might shock parents that this is what kids get up to but to them it's just everyday life. One 15-year-old boy

Growing up has always been fraught with teenage experimentation. But with adults totally out of touch with what is happening, kids feel they have nowhere to turn for support or information. Whilst sex education is taught in schools, every child we spoke to was united in saying that it was out-of-touch, irrelevant and too little, too late. Instead the boys turn to porn to teach them what they think they need to know.

Jon Brown from the NSPCC said: "Good quality sex education is absolutely critical. It needs to start actually in primary school. It needs to be age-appropriate, if we are able to help them navigate their way through these pressures."

So far society has tended to throw its hands up in horror at what the younger generation is being exposed to. There has been the hope that blocking porn might help reel in behaviour. But technology is hard to harness and opting out of porn will not stop children creating their own content. And the advent of 4G will mean not just photos but self-generated videos will be easily shared. The kids say that adults just need to accept this new world is here to stay and do what they can to help them through it.

Read the full research from the NSPCC here
Is porn changing how teenagers see sex? (Getty)