Finding good maths teachers

Here is the original version of a letter published in today's Times.

Dear Sir,
In considering the shortage of maths teachers we should remember that being well-qualified in a subject is one thing, being a good teacher is another. Schools where both qualities are combined are fortunate.
Good teachers are also good learners and teach effectively as a consequence. They know, or take the trouble to find out what needs to be taught and then set about teaching it well and in appropriate ways to their particular pupils. There may be alarm in some quarters about the shortage of maths teachers, but it may well be that many teachers are able to teach outside their subject, and may well relish the challenge of doing so. If we expect children to learn something then is it too much, when occasion demands, to expect their teachers to do the same?
In my early forties I passed GCSE Latin following six weeks self-tuition, in order to run a Latin club out of hours. At the end of a year one sixth former gained a 'B' grade which impressed university admissions tutors - Latin from a comp and gained in after-school classes. Later in my career, as a member of an educational trust, I had the privilege of observing Teach First's trainees in the classroom and was most impressed at their constructive engagement with their classes and gained the impression that they would be more than capable of teaching outside their comfort zones.
Yours faithfully,