A teenager was stabbed to death in an horrific attack after "running for his life" as children looked on in a suburban street.

The 18-year-old was knifed repeatedly and was seen shirtless and covered in blood during the attack in Hayes, west London.

An onlooker is said to have screamed at the alleged attacker to stop as the victim was knifed repeatedly in front of children as young as 11.

Despite the efforts of the emergency services to save the him, he died at the scene in Gledwood Gardens just before 4pm on Monday.

An 18-year-old man was arrested a short distance away on suspicion of murder. Detectives today said the victim and suspect were known to each other.

A witness said: "I thought it was just kids playing around. I wish I could have helped, I wish I could have done something.

"The white boy was running for his life, a young white teenager, he was stabbed multiple times.

"The boy had his shirt off and he was covered in blood.

"Then the boy kept on stabbing him and stabbing him and I walked to my wall and screamed 'stop it, leave him' and then I saw his hands going up and down and I was yelling 'stop it' while I was on the phone to 999."

The alleged attacker is then said to have walked off with a knife still in his hands.

"There was nobody there and the boy just started to walk away, he didn't run, he didn't walk fast or anything - he just walked away," the witness added.

"He did his job and then he walked away, he strolled away.

"By then, people had heard my screams and thought something happened to me and they came out, a woman was standing over the boy and other people had come to help."

She added: "I was also thinking as a mother. I did what I did as a motherly instinct as well, if the boy had run towards me I would have let him in my house, but I don't know if that would have been the right thing or not.

"You would do anything to protect someone when they're in trouble."

Eyewitness Gurdeep Chaggar, 47, a single father, said: “My daughters who are 11 and 12 came running in and said there was a guy stabbing another guy with a big knife. She came flying up the stairs to tell me.

“I ran there and saw a guy laying on his face. I saw a two inches wide gash on his back - there were two or three wounds.

“I got some towels and put pressure on his wounds. I have done a first aid course so knew what to do.”

Neighbours today described how they had heard shouting shortly before the stabbing.

One neighbour said: “There was shouting like an argument in the street and the next thing we knew there were ambulances and police cars racing past.

“There have been noisy incidents at the house where they lived but no one would have imagined anything like this.”

Another said: “We have had a lot of people going through the house where they lived and gave us constant noise problems with loud music and other disturbances. The men involved knew each other and seemed to get on but no one knew them well.”

A third neighbour said: “It is a tragedy and makes us around here fearful.”

The neighbours described the property where the pair lived as a “halfway house” run by the council.

A police cordon was still in place today, with a crime scene tent in place around the spot where the victim collapsed.

Detective Chief Inspector Noel McHugh, from the Homicide and Major Crime Command who is leading the investigation, said: “I would ask anyone who has information that could assist this investigation to contact the incident room.

“We are especially keen to hear from anyone who was in the area of Gledwood Gardens shortly before 4pm and witnessed the assault to come forward.”

At least seven young people have died on the streets of London in knife attacks this year.

Witnesses are urged to contact the incident room on 020 8785 8099 or Crimestoppers, anonymously, on 0800 555 111.