But a recent report on the state of English tuition for foreigners reveals that the main providers of lessons in basic English are further education colleges. This is particularly marked in London where they have some 65,000 students on courses in English for Speakers of Other Languages.
Across the country, FE is thought to cover 60 per cent of basic English tuition, teaching 100,000 students.
The report, from the Association of Colleges, warns that the London economy will suffer unless more teachers and courses are found for the growing population of non-native speakers.
There are already said to be more than 300 languages in the capital, a scale of diversity which rivals New York. The Greater London Authority estimates that a fifth of secondary pupils are not fluent in English, while two-fifths of primary children do not speak English as their first language.
The AoC says that one London college has doubled its provision in the past two years. But there are still not enough courses. Citizens from other European Union states already use the FE sector for English lessons and the accession of 10 new EU states in May should raise demand further.
The report calls for more investment to access the skills of the capital's immigrant population, many of them professionals. "There are likely to be negative consequences for London if non-fluent residents are less able to benefit from further and higher education and training," it says.
"The up-skilling of the population is viewed by the Government as a key condition for future prosperity and sustainable regional and national development."
Parents with a poor command of English are less able to help their children in schools. The Prime Minister's strategy unit has already noted that London parents are less likely to be involved with schooling.
The AoC report highlights a number of problems - with the behaviour of the benefits agencies prominent among them. Students have been prevented from completing apparently vital courses because Jobcentres demand they present themselves elsewhere.
Staff recruitment and retention emerge as key concerns, along with the burden of bureaucracy. One lecturer interviewed by the researchers had filled in more than 40 forms for a single ESOL student, at which point she stopped counting. Individual Learning Plans, while good in principle, were felt to be unnecessarily time-consuming, particularly in cases where the students had so little English they could not discuss their programmes. Nor does it help that many foreign students expect the teacher to be in complete control and are unfamiliar with the idea of planning their own learning.
Students found that outside the classroom their chances to speak English were very limited as they knew few native speakers. Many are highly qualified in their own country, so become frustrated at any perceived lack of progress.
Opportunities for work experience are limited, time-consuming for the college, and further hampered by the demands of the health and safety legislation.
Refugees who do not receive benefits from the National Asylum Support Services are not entitled to get free English lessons, nor are recently-arrived spouses - a situation seen as unjust by some college staff. The colleges complain that Gordon Brown's bid to improve the skills of 1.5 million adult learners by 2007 sets the bar too high for ESOL students. It is, they point out, much easier for a native speaker to reach entry level 3 in literacy than for someone who speaks only Spanish to reach that standard in English.
ESOL is distinguished from ESL - English as a Second Language - which tends to be associated with the private sector and a younger, more advantaged clientele. But the differences are not so great in practice, according to the independent language schools, who say that their spare capacity could be used to help out the stretched FE sector.
"There are many well-resourced, highly-professional and accredited-language schools which are being overlooked in the Government's plans for adult learners," says the Association for Recognised English Language Schools.
"A guaranteed class of, say, 20 needn't cost any more per head than in the state sector."
Increasing Fluency, Increasing Choice: ESOL at London's Colleges can be obtained from the Association of Colleges London Region, Rooms 204 and 206, Senate House, Malet Street, London WC1E 7HU, or at www.londoncolleges.com