Eighteen-year-old Bobbie-Jo Martin is lucky to still be walking free after her court appearance.

The awful killings involving young people around London in the past few weeks have put a national spotlight on the whole question of teenagers and knives.

It is to be hoped that appearing in court has brought home to this offender just how close she came to getting a prison sentence.

There should be no question about it. Time in a cell should be the usual punishment for anyone who goes out on the streets carrying a knife.

That’s the only way to make clear to young minds of the potentially lethal conse-quences of arming yourself in this way.

Bobbie-Jo says she now knows how serious her offence was and insists that she has stopped drinking and smoking and “won’t be doing it again”.

Let’s hope other youngsters take note and follow her thinking.

Having a knife tucked into the waistband of your trousers is a clear sign that you intend to use violence.

It also hugely increases the likelihood of someone using serious violence against you because you will be viewed as a walking threat.

Knives must be left at home.