Jodie Chesney was a keen Explorer Scout. Yousef Makki wanted to be a surgeon.

The two 17-year-olds were stabbed to death last weekend in different parts of England, plunging families into grief and igniting an intense debate about why so many young people are dying, and who is to blame.

After falling for a decade, knife crime is rising in Britain. There were 285 knife killings in the year to March 2018, the most since comparable records began in 1946.

"How many more?" asked the Daily Mail on Tuesday alongside photos of 27 teenagers stabbed to death in the past year.

Opposition politicians blame the Conservative government's cuts to police and social programs.

But Prime Minister Theresa May says there is "no direct correlation between certain crimes and police numbers."