When Henry opened his phone to a new Snapchat message from a friend, nothing could have prepared him for what he saw.

Sat within the confines of his iPhone screen was a video of his 15-year-old best friend dying, having been stabbed multiple times at a 'linkup' in Hackney, east London.

Henry, 15, watched as his teenage best friend took his last breaths, surrounded by people thoughtlessly filming him gasping for air - footage that would later spread across social media.

Brayan David Saldarriaga, from Haringey, north London, was allegedly murdered on Poplar Close on the evening of Monday May 25 among a gathering of teenage revellers. He was pronounced dead at the scene.

Footage showed screaming teenagers sprinting away from the scene and towards the Hackney Marshes, as shots were fired in the background. One girl was heard shouting: 'He got done, oh my days, yo, he got done'.

Brayan's death lays bare the deadly reality teenagers face in London, where rising violence is increasingly taking root at teenage 'linkups' that have sprung up across UK's residential areas, high streets and parks this year.

Youngsters flocked to Clapham on May 24 where a 17-year-old boy was stabbed and panic unfolded in Brighton after another alleged stabbing.

Fights also broke out on Seaham beach in Durham and in Southend, Essex, where police were filmed arresting a teenager. 

So called 'linkups' encourage a large group to meet en masse at a particular time and place, often encouraging anti-social behaviour. 

A feared mob mentality can quickly take hold at these gatherings, inciting fights and drawing gangs who arrive looking for potential targets.

Police said a fight spilled out of a house party last week, which led to Brayan's death. A 16-year-old, who cannot be named because of his age, has since been charged on Saturday with his murder.

This environment has left teenagers fearful to join their friends in Sir Sadiq Khan's London, as figures show crime in the capital has soared since the Mayor of London came to power - despite his claims it is a 'safe city'. 

Teenagers have subsequently had to become attuned to potential threats, which now includes 'linkup' gatherings. 

'I wasn't stupid enough to go to Poplar Close that day,' Henry, whose name has been changed, tells the Daily Mail.

'It is not safe in London as a teenager. Everyone should feel safe, but the current dangers young people face is never going to stop.'

Posters, created by AI, promoting these 'linkups' are being circulated on social media sites TikTok and SnapChat, encouraging teenagers to gather in what appears to be an 'organised' event.

The poster sells this pretence in sharing a location and date, along with a call to bring one's own speakers and drinks - and the promotion of the sale of drugs.

However Henry tells the Mail that many of the events are anything but safe - set up loosely by teenagers themselves, they quickly become an alcohol-fuelled arena where fights break out and violence festers.

'Sometimes nothing bad happens, it just depends on the day. But most of the time, it is just girls fighting. They fight over little arguments,' Henry says.

The danger rises sharply on the postcode. He claims this is particularly true of Hackney, rather than other 'linkup' locations of west and south London, where gang rivalry is allegedly rife as members are able to target specific people.

'Gangs don't personally make the posters but they will if they think certain people are going to go. They go to have an altercation, ' Henry says.

'I'm scared it's going to happen to me. Hackney is not a safe area because of gang violence. Every gang has beef so it will just keep going on. Civilians get caught in the crossfire.

'Gangs are not specifically trying to hit civilians, they are trying to hit gang members. So if you look like one, you can get hit. This is normally the stereotypes, mostly black people who are wearing black clothing.'

Henry, who is preparing to take his GCSEs next year, said 'linkups' normally attract teenagers aged 14 to 19 years old, who fundamentally 'just want to have fun and meet with friends'. However this can quickly turn.

The teenager credits his 'intuition' for choosing not to join his friend at the event last week, adding: 'Parties like that in Hackney do not happen. Someone was stupid enough to think it could happen, I don't know who that was.

'I just knew I wasn't going to be safe.'

Henry's fear is mirrored by his own mother's, who calls for the safety of teenagers on the streets of London. She tells the Daily Mail: 'I am always in a state of panic worrying about where my son is if he isn't home.' 

The mother watched the videos that circulated of Brayan's last moments, adding: 'There are a lot of kids but the only child who died was Brayan. Henry was shocked when he saw the video, he told me: "He died in front of everybody".

'Once I saw that video, I didn't sleep. Nobody should have died. If you have children, you fear that anything can happen. But this fear has grown with these gatherings. The children aren't safe.' 

While grieving his friend, Henry reflects fondly on Brayan, having been his friend since Brayan came to the UK as an eight-year-old from Colombia without a word of English. 

'I found out through a video that my friend had died. That isn't right. I watched him take his last breath and couldn't do anything about it. Someone just sent it to me without thinking they were capturing Brayan's last minutes alive,' he adds. 

'There are a lot of people around my age who are immature so they are going to record serious things instead of helping. The whole thing isn't right.'