Courts, hospitals and police were today dealing with the aftermath of a Bank Holiday weekend spate of stabbings, shootings and fatal beatings, many of them involving young people.

Six people were in custody today after the death of Amar Aslam, 17, in a "sustained and brutal attack" in the walled garden of a park in Dewsbury, West Yorkshire. Two of those being held were aged 12 and 13, and three were aged 15.

Meanwhile, Karl Bishop, 21, from Sidcup, Kent, was remanded in custody this morning accused of stabbing to death Robert Knox, 18, a film actor who appears in the next Harry Potter film. Bishop is also charged with wounding five other people aged between 16 and 21 during the incident in the early hours of Saturday.

A few miles away in Bromley five men were slashed or stabbed in during a brawl at the Bird in the Hand pub in Kent last night. Four men in their 30s were being questioned by police today and two of the victims were still in hospital with knife wounds to their chests and torsos.

The upsurge in violence prompted Sir Ian Blair, the Metropolitan Police Commissioner, to call on parents to ask their teenage children if they were carrying a knife. In this month alone London has also seen the fatal stabbings of Jimmy Mizen, 16, in Lee, and Lyle Tulloch, 15, in Peckham. The 14 young deaths in the capital since the start of the year is the worst toll on record.

Sir Ian said that Scotland Yard was "bending every sinew" to catch the culprits, but that knife-carrying was not just a matter for the police. "Parents have a duty now to be asking their teenagers: are you involved in this knife-carrying?" Sir Ian, speaking at New Scotland Yard, said today. "What we see with these fatalities is one life lost and another life is ruined because this person will go to prison for a very long time."

Elsewhere in Britain, a 20-year-old man was due to appear in court today charged with attacking two teenagers near East Ham Underground station in East London; two black teenagers were wounded in separate shootings in North London; and two youths suffered knife wounds in a fight outside a Nando's restaurant in Nottingham on Sunday evening.

Eight men ranging in age from 19 to 27 were arrested after a 31-year-old man was stabbed to death in Bradford, West Yorkshire, around midnight last night. A second man, aged 27, was in a serious condition in Bradford Royal Infirmary.

It also emerged that a 39-year-old man was in a stable condition in hospital after being shot in the head in the South Woodgate area of Birmingham; on Friday night a 29-year-old man was beaten to death in Hendon, northwest London; Alan Riddock, 41, died in hospital on Sunday after a knife attack in Bedminster, Bristol.

The battered body of 17-year-old Amar Aslam was discovered by two passers-by in Crow Nest Park in Dewsbury at 7.30pm on Sunday.

The killing happened close to the home of Shahid Malik, the Labour MP for Dewsbury, who called for "a change in society". He said that many young people were part of a culture where violence was seen as an acceptable way of life. "We often band together these terrible attacks as being racially motivated when the reality is that ultimately, they are just about young people," Mr Malik said. "More often than not it is not about race, it is about young people who have got involved in a culture where they feel violence is acceptable, either as an offence or in defence."

All six of those under arrest in connection with the killing are Asian, a police source said.

Detectives are investigating whether Amar may have been the victim of violence between warring gangs of youths in the park. A post-mortem examination revealed that he died of head injuries.

Detective Superintendent Chris Thompson, of West Yorkshire Police, said that the park had been very busy on Sunday because it had been a sunny day, and he appealed for witnesses to come forward. He said that Amar, who was wearing white tracksuit bottoms, black trainers and a Bench top, was found lying in the walled wildlife garden by two passers-by who rang for an ambulance.

Today large parts of the park remained sealed off with a number of police officers positioned around the area. An underwater search team arrived, along with other police vehicles and personnel.

No one at the victim’s family home was prepared to comment on the tragedy.

Karl Bishop, an unemployed man, appeared at Bexley magistrates' court charged with murdering Rob Knox in a fight outside the Metro bar in Sidcup, and with five counts of wounding with intent after five victims, all male and aged between 16 and 21, needed hospital treatment after being stabbed in the fight.

Mr Knox, who played Marcus Belby in the forthcoming Harry Potter film, was the 14th teenager to die violently in London this year.

His father, Colin Knox, described his son as "an angel on Earth without wings" and said that he was a "very positive guy" who could turn his hand to anything. He said the family hoped his son's movie role would bring attention to the UK’s knife crime problem.

Police in London today revealed that a weapons crackdown using metal detectors and scanners had led to more than 200 arrests and the seizure of 130 weapons in less than a fortnight. Police had called at 209 homes to warn parents of their children's activities.

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