The common errors referred to by Ms Leonard, which her students make at the beginning of their course, quite obviously result from their previous teachers' failure to remedy those faults in "11 years of compulsory education".
However, while the dramatic improvement which Ms Leonard and her colleagues achieve deserves approval, I would add a note of caution.
Many students, through a combination of factors such as below-average ability or low concentration levels or motivation, seem to have difficulty retaining the simplest of facts, no matter how conscientiously they have been taught.
Thus, when Ms Leonard's students eventually go to work and some sanctimonious employer berates the failure of their national vocational qualifications teachers to eradicate simple, basic English errors, she will quite justifiably be immensely irritated.
GRAHAM GRIFFITHS 25 Parliament Street Bury Lancs