I gather this is not an unusual occurrence. Certainly nobody in the garden treated it as such. Nothing was said as boys with gelled hair and girls in platform trainers flung peanuts and lemon slices with abandon. Everyone simply huddled over their drinks and hoped nothing hit them.
So, after a while, I went over and said something like "Please stop throwing food. You're spoiling the evening for others."
The group giggled, presumably on the adolescent assumption that any remark made by an adult is, of necessity, absurd. One girl said the bar was owned by her friend's uncle.
"That still doesn't give you the right to throw food at people."
"Take it up with him," she said.
So I did. "It's just high spirits," said Uncle warily, as people began to retreat indoors.
"No it's antisocial, and you're in charge," I told him.
Eventually Uncle went outside and made a half-hearted attempt to be liked, which achieved absolutely nothing.
Much to my friend's discomfort, I insisted on finishing our drink because it seemed important that the Gelled Ones shouldn't feel they had driven everyone away, even though they had.
I felt despair about the lack of collective responsibility we adults had shown. When I was young, strangers remonstrated with you for dropping litter or bashing into other people. Nowadays it seems we leave discipline to others: policemen and teachers mainly. No wonder kids have problems with both groups if those are the only adults who will challenge their right to rampage.
But most of all I felt despair about "Uncle", who was so keen to be popular he was incapable of discipline, even when he tried. People in positions of responsibility aren't necessarily there to be liked and any who court popularity at the expense of doing their job - like Mr Jolly - are ducking that responsibility.