My Lords, I deplore the carrying of knives, as do all of us in this House. I shall make two short points to support the noble Lord, Lord Marks. First, I am sad to disagree with the noble and learned Lord, Lord Mackay of Clashfern, but my experience of teenagers is that those between 16 and 18 would probably not take the slightest notice of a deterrent, as has already been said. Those who are slightly older—over 18—might, but from my experience as a family judge, I doubt that this would be a deterrent to 16 or 17 year-olds.
Secondly, I sat occasionally in crime, and was not very good at it, but I find it quite extraordinary that successive Governments seem totally unable to trust the judiciary to come to the right conclusion. We know from previous speakers that judges already have all the powers they need to deal with a second offence, to deal with it strongly and to put people away for much more than six months. For those two reasons, I very much support the noble Lord, Lord Marks.