London's police chief announced a crackdown on teenage murders after a teenage boy was arrested over the 15th such killing in six months.

Sir Ian Blair, the Metropolitan Police commissioner, said the force would launch Operation Curb to proactively target known gangs in all of the capital's 32 boroughs.

"We now have a situation where 15 teenagers have been murdered since January," he told the Metropolitan Police Authority yesterday.

"Two to three dead teenagers a week create a sense of fear that is just completely unacceptable in the 21st century."

The announcement comes after the devastated Lorraine Dinnegan, whose son Martin was stabbed to death in Islington on Tuesday, called on police to do more.

"Why is it happening, why is it still happening?" she pleaded on the north London street corner where her son died of stab wounds to the chest.

"How many more victims is there going to be?"

"The police can do more. They need to be out more in local areas to deter clumps of teenagers hanging around together."

On Wednesday night police arrested a 15-year-old boy over Martin's murder.

The schoolboy, described by his mother as a "lovely" son who was popular and did well at school, was attacked in Tollington Way on Tuesday evening when he and some friends became embroiled in a row with up to 20 youths.

Martin is one of four teenagers killed in the last six days.

Just hours after Martin was killed, 18-year-old Abu Shahin died after a street attack by two suspects in Ilford, east London.

At the weekend, Annaka Pinto, 17, was shot dead in a bar in Tottenham, north London, while Ben Hitchcock, 16, was stabbed to death in a mass brawl of up to 40 youths in Beckenham, south-east London.

Yesterday Sir Ian said all boroughs should unite to act on the violence.

"What we have decided to do is to create a special operation to deal with this over the summer.

"The spread of these killings is not in any one particular borough," he added. "We have got to do something about it."

Measures will include more patrols by officers and PCSOs to "offer reassurance" to local communities.

Borough intelligence teams will engage with teenagers and children known to be involved in serious violence to stop them becoming a victim or offender.

Officers will work on an intelligence database, mapping and understanding who the individuals engaged in gang crime are, who their affiliates are, what drives them to commit crime, and what can be done to prevent them from getting involved in the first place.

Stop and search must be used to find youngsters carrying knives or guns, Sir Ian added.

"Some of the weapons are of such a significant size that it would not be a difficult thing to find had somebody been stopped and searched."

A STRING OF MURDERS

Fifteen teenagers have been murdered in London in the last six months.

  • June 27: Abu Shahin, 18, of Manor Park, east London, dies after being attacked in the street in Ilford, east London, by two suspects. A 20-year-old man is arrested.
  • June 26: Martin Dinnegan, 14, is stabbed to death on the street in Islington, north London.
  • June 23: Ben Hitchcock, 16, is stabbed to death in a fight involving as many as 40 youths wielding chains, poles and pick-axe handles in Beckenham, south-east London. Fourteen teenagers are arrested in connection with the murder, but are all released on bail.
  • June 23: In the early hours, 17-year-old Annaka Pinto is shot dead in a fight at the Swan bar in Tottenham, north London. Three people are arrested and then bailed.
  • June 19: A-level student Sian Simpson, 18, is stabbed to death in Croydon, south London. Another 18-year-old girl, unemployed Chelsea Bennett, is charged with the murder.
  • May 28: Danielle Johnson, 17, is stabbed and beaten in broad daylight in Palmers Green, north London. She dies more than a week later.
  • April 6: Paul Erhahon, 14, is stabbed to death in Leytonstone, east London. A second boy, 15, is critically injured in the attack. Seven teenagers are charged with murder and attempted murder.
  • March 17: Adam Regis, the 15-year-old nephew of Olympic sprinter John Regis, dies of a single stab wound to the chest in Plaistow, east London, on the way home from the cinema. Ten youths, aged between 16 and 20, are on police bail.
  • March 14: Kodjo Yenga, 16, is stabbed to death in Hammersmith, west London. Eight teenagers, aged 13 to 16, are charged with his murder.
  • February 14: Billy Cox, 15, is gunned down on the doorstep of his home in Clapham, south London. At the time, he was serving a 12-month supervision order for burglary and was electronically tagged and under a curfew. One man is on police bail over his murder.
  • February 6: Churchgoer Michael Dosunmu, of Peckham, south London, is shot dead in his bedroom just days after he celebrated his 15th birthday in what police believe was a case of mistaken identity. Two men are charged with his murder, and three other men and a 16-year-old boy are on police bail.
  • February 3: James Andre Smartt-Ford, 16, of New Malden, Surrey, is gunned down in front of hundreds of people at Streatham Ice Arena in south London. Four teenagers are on police bail.
  • January 24: Jevon Henry, 18, is stabbed in the heart on an estate in St John's Wood, north London.