One of the great pleasures of reaching retirement age is that you get the chance to make a valedictory speech. For many teachers the retirement message is unequivocally positive. They see the achievements of today’s students as surpassing those of their predecessors. Yet, sadly, some teachers leave the profession feeling depressingly downbeat, bemoaning a lamentable fall in standards compared with those of yesteryear.

Was there once a golden professional age in which every teacher was a saintly generous colleague - like Mr Chips? And are today’s teachers only interested in asking, “What’s in it for me?” - a depressing cross between Gradgrind and Jobsworth, prepared to do their duty but complaining at every new turn of events?

The truth, according to the latest TES survey of teachers’ lifestyles (page 1), is more complicated. The present generation of teachers may operate in a more mistrustful atmosphere. And they may in consequence face more bureaucracy, regulation and accountability than ever before. Nevertheless, they include - to a greater degree, I would argue, than in times past - the same core of generous committed professionals prepared to walk the extra mile.

They are not in teaching simply for the money. They are in it, as they might privately admit, to make a difference to their pupils’ life chances.

They care not just about their pupils but about the adults they will become. Such teachers are learners themselves who believe in the limitless potential of their pupils. Not for them reliance on a theory of general predictable intelligence, but rather on the transformability of each and everyone they teach.

Failure of the child to learn is not indicative of his or her ability, but a teacher’s own temporary failure to find the correct key to unlock the mind and open the shut chambers of the heart of their pupil. They see great effort to learn on the pupil’s part not as a sign of low ability but of determined character, which in the end and with their help will surmount barriers to successful learning. In doing so, they provide a master class of what government spinners now call “personalisation”.

If the motivation of such teachers to pass on the knowledge, general human skills and values that will develop so many of their pupils into adults committed to social justice as well as their own fulfilment sounds hopelessly romantic and old fashioned, then they are stubbornly antique. If teachers also get to change the world in so doing, then they dwell in the future as shamelessly successful social engineers.

Of course, these teachers don’t count the cost. They seem to give almost every minute of every day to thought and action about improving their practice and their professional work, which is a major rationale of their life.

I came across two such teachers on separate occasions recently - one at the end of her career, the other at the start.

Sandra was retiring in Birmingham after a lifetime inspiring children. In a This is your Life-type presentation, there was evidence of residentials exhaustively undertaken, school productions that went hilariously wrong, and countless examples of acts of private kindness.

Her present charges wept openly as they intuitively recognised that their younger brothers and sisters would not encounter the same extraordinary, life-changing educator from whom they and their elder siblings had learnt so much.

Lucy is in her third year of teaching. When I first met her, she was assigned by her shrewd London secondary headteacher to be my school guide.

Her conversations with passing staff and children seemed endless. As we popped into her class, which was being covered by a colleague, she momentarily took over the performance of her dance group with a mere glance.

Her three lunchtime clubs and one after-school society had waiting lists.

The next spring, I attended the school’s first public dance display by a series of groups. A year later, there was a play. Somehow or other Lucy had found time to produce both, of course - as she would say, with the generous support of so many of her similarly committed colleagues What connects Sandra and Lucy across the generations? Certainly, all the qualities and habits I’ve mentioned earlier, but also a vibrant love of life and work. To neither is life a “brief candle”, but rather a “splendid torch which they’ve got hold of for the moment as they seek to make it burn as brightly as possible” before handing it on to future generations.

In the end, there are two sorts of school professionals - the energy creators who see glasses as half-full and can always spot a silver lining, and the energy consumers who are habitually half-empty, dwelling in an overcast smog of clouds.

The battle for the heart of any school is one between the “how we coulds”

and the “why we can’ts”. Fortunately, the example of Sandra and Lucy is contagious. They are merely representative. And fortunately, there are many more in today’s schools. So the energy creators are winning. Of course, they get up ridiculously early and stay up far too late, ending the day exhausted while the rest of us are merely tired.

As we enter 2006, it is fortunate for our schools and our future that there is a particularly rich seam of such teachers. Ministers and politicians may huff and puff as much as they like about their latest policies, practices and protocols, but they aren’t worth a row of beans without the teachers I have described here. It is they who make the difference.

Tim Brighouse is the Government’s chief adviser for London’s schools