Murder investigations have been launched after two boys were stabbed to death in separate incidents within an hour of each other on Thursday evening, making 2021 the bloodiest year on record for teenage homicides in London.

A 16-year-old boy was fatally wounded at Philpot’s Farm, Yiewsley, west London, and was pronounced dead at 8.25pm.

It followed the fatal stabbing of a 15-year-old boy in Ashburton Park Croydon, south London, who was pronounced dead at 7.36pm.

A 15-year-old boy has been arrested on suspicion of murder in relation to the Croydon stabbing, police said.

Neither victim has been named yet by the Metropolitan Police

Scotland Yard said there was no intelligence to link the two incidents, more than 20 miles apart, but called on parents to talk with their children about the impact of carrying weapons.

Police Commander Alex Murray, in a direct appeal to parents from the scene in Croydon, said: “If you have concerns, talk to your kids.

“Make sure they’re not carrying knives, make sure they’re not hanging around with kids carrying knives.

“We don’t know who has knives but we can find out and we can stop them hurting someone or being hurt.”

He said the Met was “absolutely committed to bringing those offenders to justice”, and added: “This is what happens when knives are carried and we all have a role in relation to tackling knife crime.”

Detective Chief Inspector Jim Shirley, who is leading the Yiewsley investigation, added: “I am urging anyone with information, or who saw the attack, to come forward and speak with us.

“We need to establish what happened and find the person who is responsible.”

The double tragedy brings the total number of teenage killings in the capital in a calendar year to 30 – passing a previous peak of 29, set in 2008.

The seriousness of the situation was further underlined by Pastor Beryl St James, from Shiloh Worship church and charity in nearby Thornton Heath, who told the PA news agency she had just received a call from a parent who had found a knife in their child’s room that morning.

Also speaking from the scene, she added: “I know we have to work and we all have duties to fulfil, but as a parent you cannot think that’s it OK to leave the state to continually look after your child.”

Patrick Green, chief executive of anti-knife crime charity the Ben Kinsella Trust which was set up in 2008 following the fatal stabbing of 16-year-old Ben in north London, echoed Mr Murray’s comments.

He said: “Knife crime is accepted by this generation as part-and-parcel of growing up and that’s completely unacceptable.

“It shows that not enough has been done and if I’m being really critical then I’d say the approach to tackling it has been scattergun.

“We have to sustain our response to knife crime, it has to be over the long term and not just one- and two-year funding for projects.

“It is a societal problem which will continue unless it is addressed properly.”

The two murder investigations will again prompt discussion about the possible causes of youth violence, with experts suggesting this includes a rise in the number of children who are vulnerable, increased pressure on services such as policing, and social media fuelling conflict.

Anthony King, chairman of the MyEnds programme which aims to tackle knife crime in London, told reporters at the scene in Croydon: “Sadly it’s because we’re having a lot of breakdowns in schools, in education, young people are being excluded too quickly, some for minor incidents, there’s breakdown in the homes.

“Parents – if you see a bread knife or bun knife missing from the home, please speak to somebody, please contact an agency or an organisation and let the teachers know.”

London Mayor Sadiq Khan said he was “devastated” by the double tragedy.

He said: “I refuse to accept that the loss of young lives is inevitable and will continue to be relentless in taking the bold action needed to put an end to violence in our city.”

Scotland Yard said police were called to the Croydon stabbing shortly after 7pm.

They gave first aid to the boy before the ambulance service arrived but he was pronounced dead a short time later.

Police were called to the stabbing in Yiewsley shortly after 7.30pm, where they found the 16-year-old victim suffering from a puncture wound.

He was also declared dead at the scene.

The victims’ family members have been informed but neither boy has been formally identified, Scotland Yard said.

Post-mortem examinations will be held later.