SIR — My daughter and I were walking our dogs on Harpenden Common last Friday evening at about 7.45pm on the Walkers Road field. We could hear a small group of young people laughing and joking while sitting on the grass. They may have been a little older

SIR - My daughter and I were walking our dogs on Harpenden Common last Friday evening at about 7.45pm on the Walkers Road field.

We could hear a small group of young people laughing and joking while sitting on the grass. They may have been a little older, but sounded as if they were aged nearer 16 than 18. They appeared to be enjoying themselves quite harmlessly and we continued our dog-walking circuit without further thought of them.

The following morning in exactly the same location where they had been sitting, I collected 12 empty cans of 7.9 per cent continental lager. That is not a misprint - 7.9 per cent!

These questions come to mind: who (illegally) sold them this incredibly strong brew; and did their parents bother to know where they were, what they were doing and did they notice what sort of state their children were in the following morning?

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