According to police, Rizwan Darbar and his two friends were sitting in West Ham Park, listening to music on a mobile phone, when three youths approached and demanded the handset and money. When he began arguing, one of the trio stabbed him.

The 17-year-old was immediately rushed to the hospital where he succumbed to his injuries. His murder was the 21st knife or gun killing of a teenager in the city this year.

However, Darbar's death has sparked a wave of crisis meetings at Scotland Yard, where detectives are trying to clamp down on the escalating knife problem on the streets of London, according to the 'Daily Mail'.

"Rizwan had done nothing whatsoever that would explain that level of violence. At the moment it appears this was an unprovoked robbery with gratuitous violence.

"The guys were reasonable lads doing nothing other than listening to music. The victim had very little warning. Our advice is always to hand over the phone," Detective Chief Inspector Matt Horne was quoted as saying.

The youth believed to have stabbed the teenager is said to be of mixed race, aged around 18 and about 5ft 8in. His two companions were black, according to the police. "We are trying our best to arrest them."

"Rizwan has never been in any trouble. He was a devout Muslim who was fasting and praying at his local mosque every evening for Ramadan. He was born during Ramadan in 1990 and now he has died during Ramadan too," Darbar's devastated father Ayub, a launderette owner, was quoted by the daily as saying.