The Border & Immigration Agency has recently introduced a requirement for English language skills for those who apply for British citizenship or for indefinite leave to remain in the United Kingdom.
There is a wide range of English language courses offered by local UK colleges for all different levels of ability.
Some colleges offer free or cheaper courses to some groups of people, for example the retired or those on state benefits.
Wherever you live in the UK you will be able to find local information about English courses that are available.