The family of murdered teenager Stefan Appleton is calling on London Mayor Boris Johnson to speak publicly about knife crime.

Stefan, 18, was stabbed to death at Nightingale Park in Canonbury on June 10. It was one of a spate of knife attacks in Islington this year.

Now his grieving family has started a petition: “Drop the knife, think about your life”. In it, they challenge Mr Johnson to publicly address issues associated with youths and knife crime, including education and monitoring.

Stefan’s second cousin Victor Sylvester, 57, set up the online petition. He said: “This problem has been around for a long time, but knife crime seems to have gone up in the last year. In particular, young people seem to be involved.

“There’s a whole plethora of reasons why it happens, from education to frustration to broken families. We need people to be educated.

“It seems to be that some young people can’t have a conversation or disagreement and leave it at that. They don’t know how to do this and it ends in violence.”

The petition has so far received just under 900 signatures, and Mr Sylvester, of Enfield, said: “I thought it would be more. I can’t say I am pleased, I was aiming for 10,000 given the population of London. But I think it’s a lack of exposure. Everyone I have spoken to has signed it, so I am just appealing to friends of friends to do the same.

“I think Mr Johnson can and should speak out on this. Our mayor is increasingly in charge of more and more and education is one of those things.”

Asked how the family was holding up, he said: “Everybody is still grieving. It takes time. But we are focusing our energy on doing something positive.”

To view the petition, visit you.38degrees.org.uk/petitions/drop-the-knife-think-about-your-life-1.

Two 16-year-old boys are in custody after they appeared at Highbury Corner Youth Court accused of Stefan’s murder. A plea and case management hearing will take place at the Old Bailey on Friday, September 4.

Three other boys aged 16 are due to answer bail this month. Another 16-year-old boy, arrested by Suffolk Constabulary in Ipswich on suspicion of murder and possession to supply class A drugs, was re-bailed to a date in September.