Two weeks earlier, Jimmy Mizen, 16, was killed during a scuffle in a baker's shop. His throat was slit with a shard of glass as he tried to help defend workers from a youth who was robbing the shop. His killer has yet to be found.

According to Scotland Yard, there are 169 'baby gangs' in London alone, with more than 5,000 teenagers involved. In the capital, 52 teenagers on average are stabbed each week. And gang members are getting younger and younger, with some still at primary school.

Authorities fear that some schools are becoming unsafe for pupils. According to a survey carried out by Tuned In, a market research company specialising in youth issues, one in three teenagers thinks it is acceptable to carry a knife for self-defence. In addition, half of the youths interviewed said they knew someone who had been the victim of a knife crime.

Teachers in Britain have now been given the right to collect proof of students' gang membership by examining their computers and mobile phones.

Meanwhile, police have decided to scout London's youth courts and encourage witnesses and victims of knife crime to testify against their attackers. Many gang crimes are surrounded by a wall of silence, with young victims often reluctant to identify their attacker out of fear that, sooner or later, another gang member will take revenge on them for speaking out.

Since 1996, Kids Company, a youth charity organisation founded by psychotherapist and 'Woman of the Year 2006' Camila Batmanghelidjh, has been trying to help teenagers involved in gangs. Or, as Ms Batmanghelidjh has said, those 'kids who sleep with knives under their pillows'.

'My dream is to make the public understand that this violence is a public health issue, not a criminal justice issue,' Ms Batmanghelidjh told The Independent.

Kids Company is helping 12,000 at-risk children, providing them with meals, shelter and psychotherapy. And it works.

Dawn Howley is in her 20s and now works for Kids Company. Previously she was one of the youngsters who approached the organisation for help. Having been in local authority care as a child, she knows what it is like to live at the edge of society.

Ms Howley says the recent rash of killings all have the same common root.

'Gangs operate for many vulnerable children and young people as a substitute family,' she said. 'Many do not have an adult that can take care of them so they turn to the street. Social services who are supposed to look after vulnerable children cannot cope with the scale of the problem.

'The vulnerable child who has no food, no shoes, will turn to the street for survival. The young children become targets and are used as drug runners.

'The children all have different stories,' Ms Howley said, 'but the majority of our children have suffered extreme trauma. Many arrive homeless, undernourished, and present with various mental and physical health problems. Many of these children are invisible, no birth certificates or passport.'

This is what Ms Batmanghelidjh calls 'a new syndrome that has to be named: the social and emotional deprivation that is creating a new kind of brain'.

'The fascinating element in all these children's lives is the absence of a functioning parental figure,' she says. 'If you really think about it, if you don't have a parent; there is no food in the house; no one washes your clothes or organises socialising for you; you don't get taken to the GP, the dentist or the optician; you live in chaos.'

Although England - in particular some of big cities like London, Liverpool and Manchester - has developed a single type of gang culture, it is a relatively recent phenomenon. Scotland's youth-gang scene is different, and much older.

In Glasgow - the most violent city in Britain - the murder of a teenager is barely reported in the media because it is so commonplace. Gangs have existed in Scotland for more than half a century, with membership sometimes being passed from father to son, but more often from older to younger brother.

'Bluntly, young men and women in Glasgow don't necessarily join gangs, they don't sign up to them, they don't become 'members', they don't go through initiations, they don't [always] even have obvious leaders. They are born into their gangs,' David Leask, an award-winning journalist who has covered Glasgow's gangs for years, says.

'The chances are that their older brothers, their fathers, their uncles, even their grandfathers were in the gang. That is because a gang, especially in and around Glasgow, is deeply territorial. Asking somebody what gang they are in is the same as asking them where they come from.'

As of 2002, a Scottish male aged 10 to 29 was five times more likely to be murdered than his counterpart in England. There are nearly 120 active territorial street gangs in Glasgow alone, with up to 100 more in outlying areas and at least that many in the rest of Scotland.

A conservative estimate would suggest that out of a population of about 600,000, there are 2,000 active gang members in Glasgow alone. It is not unusual for parents in the city - especially fathers - to take their children to see gang fights, Leask says.

'I have seen young mothers with pushchairs turn up in parks and wasteland to watch their partners fight, especially on a sunny summer evening. Fights are between people from different communities, sometimes representing as few as two or three streets, sometimes entire housing estates.'

The battlefields for these fights may be the same place time and time again, and are often on roads, railways or bridges. One of the most common ways to be killed in a gang fight is to be knocked over by a car or a train, or to drown in a river.

But don't call gangs 'baby' in Scotland, Leask warns.

'Scottish teenage gangs typically contain several age groups. There will be young children who play at fighting, anywhere up to 12 or 13. Then there are teenagers, who actually do the fighting, with those aged, say 14 to 17, being the most active. Then there are older boys who may have either stopped fighting or who are involved in more serious crimes.'

Leask says some of the worst violence may occur years after young men have stopped participating in gang fights, when they may be remembered by a former enemy and stabbed in the street. Gangs may also act as a gateway to more dangerous crimes, Leask says, with teenagers earning 'a degree in crime' by working as runners or lackeys for more serious criminals.

Alcohol abuse, which is a serious problem among teenagers in Scotland, further contributes to the problem. Many teenagers are intoxicated when they participate in gang fights.

'In general, Scotland has a far more serious problem with drink and drugs than England,' Leask says. 'Violence is making a real impact on life expectancy, which is far lower in, say Glasgow, than in London.

In the Glasgow suburb of Calton, home territory of the Calton Tongs - a gang which dates back generations - male life expectancy is 56. That is partly because of deaths and injuries from gang crime.

Although gang fighting is still a predominately male activity, girls are also increasingly involved, Leask says.

The British government has launched a GBP3 million (HK$45.87 million) campaign that involves showing scenes of violent stabbings on television each day. It aims to teach young people about the brutal effects of such crimes, but will it work? Not a chance, Ms Howley says.

'We need to value childhood again and make sure these vulnerable children are given real, viable alternatives to the gang and street culture. Child abuse needs to be stopped; child poverty ended. It is a guarantee that if these areas were tackled, we would not be seeing the level of violence we see today.'