How should students coming to the UK to follow an English Language course demonstrate that their English language skills are at the appropriate level?

Students studying English must be studying at Level B2 of the European Common Framework of Reference (CEFR) for Language. This was raised from level A2 (beginner) to B2 (intermediate) level on 3 March 2010. The only exceptions to this is for overseas Government sponsored students and those on unconditional pre-session courses as a preparation for a full degree course.