Three young thugs were caught on camera carrying out a "shocking" murder bid on a 13-year-old boy on board a busy train.

The trio - aged 16, 15 and 13 - pounced on their victim shortly after he got on at Glasgow's High Street station on October 15 2021.

Footage of the horrific crime - also captured on Snapchat by one of the assailants - ended up being widely circulated online.

The victim was left brain damaged and missed two years of his schooling.

The attack occurred just 24 hours before another teenage boy was murdered on the platform of the same station.

The three thugs now face being locked up after they each pleaded guilty to an attempted murder charge at the High Court in Glasgow.

They will be sentenced next month.

None of the boys involved can be identified due to their ages.

Prosecutor Lorraine Glancy KC said soon after the victim and a friend got on one of the trio was heard stating: "Let's do this."

CCTV from the train played in court saw the three racing towards the 13-year-old, who immediately ran off down the carriage.

Miss Glancy told the hearing that one of them appeared to be filming on his mobile phone what was happening.

They eventually caught up with the victim, who stumbled and fell to the floor.

The 13-year-old ended up unconscious with the graphic CCTV showing him being repeatedly stamped and jumped upon during the brutal 20-second attack.

Miss Glancy said one of the thugs used the train seats to get "leverage" to attack the stricken boy.

A woman appeared to angrily remonstrate with the trio before they got off at the city's Bellgrove station leaving the 13-year-old for dead.

Footage captured two of them hugging each other after they sprinted upstairs onto the street.

Other passengers went to help the unresponsive teenager before mercy crews attended to him after the train stopped.

The court heard he had suffered a significant brain injury, a fractured collarbone as well other bruising and swelling.

Miss Glancy said the boy has fortunately made a good physical recovery, but continues to have behaviour and memory issues, which are likely to be lifelong.

The ordeal saw him miss third and fourth years at school. He has also been treated for PTSD.

The hunt began to catch the attackers.

The hearing was told the mum of the oldest of the three called police after her son confessed he was involved.

He then claimed to officers he would be "honest" with them and that he had "stamped" on a boy's head.

The thug added: "There was loads of us - not just me."

The other two were also arrested having been identified from the footage.

Tony Lenehan KC, defending the oldest thug, told the court: "It is a dreadful video to watch. I do not shy away from that."

He added the teenager did not "come from the sort of household" involved in crime.

Frances Connor, the lawyer for the then 13 year-old attacker, said he had little recollection of the incident.

Lord Scott remarked: "If he did this, was not under the influence or has no memory, that is more alarming."

The other assailant's solicitor-advocate Billy Lavelle told the judge the teenager had "changed dramatically since this terrible incident."

Lord Scott deferred sentencing until April 17 in Edinburgh and agreed to continue bail for all three.

He stated: "The damage caused (to the victim) is going to be lifelong.

"It was broad daylight with a lot of people travelling on the train.

"That is a worrying aspect to how out of control all three became."

Addressing the trio directly, the judge further said: "What everyone has seen is shocking violence. It is truly sickening.

"I need to find out more about each of you. Allowing you to stay on bail should not be taken as an indication what I will do.

"I do not know why what happened, happened. Do not make any assumptions what will happen next time around."

Conditions of bail included a daily 7pm to 7am curfew and the unusual step of all three being ordered not to contact each other.

Just a day after this incident, Daniel Haig - then 16 - stabbed to death 14 year-old Justin McLaughlin at High Street station.

Haig was handed a life sentence in August 2023 and ordered to serve a minimum 16 years behind bars.