Why doesn't the Queen do something to tackle Knife crime?

Because its not her job, though reading some of the posts on the royalty section over the past few months, Im wondering what her job is.

She just spent 16 million on more knifes for England if I read it right.

Your confused that is the job of the Prime Minister.

She doesn't have an input.

But like me, she would probably colonise the lot of them from juvenile age; and let them kill each other.

Quicker than ethnic cleansing.

That is what parents should be doing. You can't complain about having a nanny state when it suits, but then expect the authorities to clear up the mess.

What, personally?

She's over 90, and the miscreants are all on mopeds.

That is what HM's Constabulary does under direction of the Home Secretary.

That's not up to the queen. She has duties pertaining to her station as monarch.

The people who need to do something regarding knife crime are the government and authorities like police departments.

She has a government to do that. Their idea of cutting crime is to cut police numbers.