It seems I am not the only one to have noticed how many children go downhill rapidly when they hit secondary school. What surprises me is why anyone should be surprised.

Pupils go from a tight, nurturing environment at primary, with teachers who know them inside out, surrounded by support staff, jannies and dinner ladies who all know every child by name.

There is no escape. Forgotten homework is followed up, careless work gets redone, each child is given a set amount of work to do in maths and language at their level - and it gets finished and marked every day. Every lesson will be organised to include everyone, with differentiated group work. A primary school is a small but efficient community. Trouble in the playground will be reported and dealt with immediately. Every teacher will be aware, and the culprit will know to keep his or her head down for a day or two.

Then there is this sudden freedom at high school, where few staff will know the children, or their backgrounds or what they are capable of. For the very bright child encouraged to shine in a primary school, it can be a decline into boredom. Few get extension work or the positive feedback they need to thrive.

At the other end, lazy, crazy and daft kids flounder. After seven years of being given differentiated work, they are expected to cope in mixed- ability classes. Many are level B or C, some are level A. Bad behaviour covers their inability to do the work. Nobody even notices if they join the big boys behind the bike shed at break.

Secondary teachers see more than 100 pupils a week, contend with national exams and the marking involved, get involved with curriculum development and face often very challenging classes further up the school. How many have the time to keep a close eye on first-years?

So by third or fourth year, we have the great illiterati - kids who can’t be bothered, who have sunk well below the standards they had when they arrived. They are rude and waste the days for the decent pupils in the lower sections who want to learn and do their best, but have no chance.

Their parents are concerned, but can do little at home to change things and we are wrong to point a finger at them without being aware that three more point back at ourselves. The slump in achievement is not down to a boring curriculum, but because we do not demand high-enough standards. And we do not demand them because we too are exhausted by the lack of effort and poor behaviour of so many of our pupils - a vicious circle.

It is a tragedy, and one that could be avoided. First-years need group work, they need strict boundaries, and we need to catch the vulnerable children before they begin to fail - because we won’t ever get them back once they have.

Penny Ward is a secondary teacher.