I think we do need to be very careful of the "if it was good enough for me it is good enough for them" mindset. Of harking back to some golden age when men were men and schoolchildren knew their place. We are living in different times.
There are, it seems to me, 3 basic problems:
Size - as I said upthread - if you herd children together en masse, discipline becomes the prime focus and education inevitably takes a back seat.
Relevance - our school system is based on the old public school model and politicians judge the work of schools on how they match up to that "ideal." Just look at Gove with his back-of-the-envelope national curriculum obsession. The question that needs asking is - how relevant is that curriculum now with its emphasis on academic skills? Just take a look at the maths curriculum now - my children could not see the relevance of the abstruse concepts that they knew would play no part at all in their futures, and it is even worse now. A lot of the concepts are only of use to maths teachers. I did Latin and found it fascinating, but that is because I am the sort of person who was interested in that sort of logical thinking and I had an academic brain. In the same way the maths curriculum appeals to those who have that sort of academic brain and are happy to delve into that - but for the vast majority of students, they know that what they are learning is irrelevant. And beyond their abilities - and puts them off learning - and leads to them messing about. If you know you don't stand a cat in hell's chance of understanding it, and know that you will never use it, then why not mess about? Why not take your revenge on a system that makes you look a fool?
The content of school curricula needs re-examining. The priorities need re-examining. The way in which subjects are taught needs re-examining.
Teachers are tearing their hair out trying to do the best for their pupils, whilst being forced to pump them full of stuff that both parties know is not relevant to their lives, rather than being free to use their own professional judgement and humanity about what each of their pupils need. And in the meantime they are expected to police uniform policies, collect endless stats for OfSted, prepare pupils for the ridiculous SATs and look over their shoulder at every moment for whether they are deviating from the curriculum. Good teachers are being lost, not because of the pupils and their needs, but because of the system that devalues their professional skills and leaves them picking up the pieces for a a system not of their making and for failures in social policy outside the school.
Home - many youngsters come from homes where poverty and generations of unemployment are the norm. It was indeed so for previous generations, but the presence of the media and its instant quality make these young people aware of what they are missing in a way that is new. Their own parents are the product of an education system in which they did not feel valued or included and this, along with their practical problems of being unable to make ends meet, mean that they are not always supportive to the schools. They do not engage as they have bad memories themselves of their schooldays. The very pupils with whom the school needs most to engage are the ones who are least likely to do so.
The answer to all this is not to institute draconian measures (as this head has done) which will further alienate pupils - it is to take a long hard look at the system itself and its social context and ask where it is going wrong and how it is failing our children.