Well I think the devil is in the detail here. From gov announcement...
'The plans announced today will be backed up with a first of its kind three-year wider funding package for Youth Justice Services, worth over £320 million, giving them more certainty to invest in the future, and roll out longer-term programmes to help even more young people. '
So it's more money for YJS. Not necessarily a bad thing of course, but I think the underlying focus is to lower the number of kids in custody. Again, not necessarily a bad thing. However, some young people need to be in custody because they are dangerous. And knife carrying is very dangerous...
Previously all kids carrying a knife would go through court and if found guilty community order / custody. This appears to bypass this, and is being used like a caution with conditions, in effect.
There's a number of things in the gov statement that are political swerve imho. All kids coming into contact with criminal justice system are already mandatorily known to YJS. That's not new.
Overall, my initial impression is that this is financially driven and a way to justify managing knife crime out of custody.