The devastated mother of a 14-year-old boy stabbed to death in the latest of a string of teenage murders asked: "How many more victims is there going to be?"

Speaking today on the Islington street corner where her son Martin died last night, Lorraine Dinnegan said she felt "terribly numb".

Police said Martin was attacked in Tollington Way, north London, after he and some friends became embroiled in a row with another group of up to 20 youths at around 8.30pm.

"He's a lovely boy, he doesn't deserve this, nobody deserves this, it's horrible," his mother said. "He was a very popular boy, he was well-known and did very well in school."

She knew within minutes of his death.

"One of Martin's friends phoned my eldest son to say Martin had been stabbed and they didn't think he was breathing."

Angela Fitzgerald, 53, a friend of the Dinnegan family, said Martin had left two 17-year-old friends to buy chips on his way home shortly before he was attacked.

"They weren't very happy about leaving him, so they went back," she said. They saw a row going on and saw Martin fall to the ground.

"He was lying on his back, they tried to call to him. He was very white and then started to go blue and his eyes were just staring.

"He gasped and they tried to get him up, then they saw blood all over his back. They tried to save him."

Mrs Fitzgerald said Martin had been assaulted in nearby Holloway Road about two months ago. Another boy was stabbed in the same incident.

"The boys Martin hung around with were good lads, they didn't carry knives," she said. "There's a lot of crime in the area."

By late afternoon, a growing mound of flowers had been laid at the scene. Groups of teenage boys, some openly sobbing, came by throughout the day.

On a bouquet of white and red roses, Martin's parents and five siblings James, Anthony, Gerald, Lorraine and Leeanna wrote: "Martin, remember a thousand years on earth is one day in heaven. It won't be long until we are all together. You will be sadly missed."

Martin's mother said: "I think I'm in shock at the moment, I've got this terrible numb feeling. I just hope the police can catch them.

Mrs Dinnigan added: "How easy is it to stick a knife in someone? To take their life?

"Why is it happening, why is it still happening? How many more victims is there going to be? I'm lost for words.

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

A large area around the scene was cordoned off for forensic examination.

Last night paramedics treated Martin for stab wounds, but he died at the scene at 9.07pm.

"This was a vicious attack carried out in daylight on a busy street," said Detective Superintendent Richard Heselden.

"The family of Martin are understandably devastated about the loss of their son and need answers as to why this has happened."

Anyone with information can call police on 020 8345 3715 or Crimestoppers, anonymously, on 0800 555 111.

A STRING OF MURDERS

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

  • Today: 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.
  • Yesterday: Martin Dinnegan, 14, is stabbed to death on the street in Islington, north London.
  • Saturday night: 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.
  • Saturday morning: In the early hours, 17-year-old Annaka Keniesha Pinto is shot dead in a fight at the Swan bar in Tottenham, north London. Three people are arrested and then bailed.
  • Last Tuesday: 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.