What TEFL Qualifications are there?
Where can I find information about Language Schools offering TEFL courses?
How good must my English be to enrol on a TEFL course?
Do I need a degree to enrol on a TEFL course?
Teaching at Schools in the UK
How good must my English be to enrol on a TEFL/TESOL course?
If you want to qualify as a TEFL teacher in the UK, you should be able to demonstrate a very high standard or oral and written English, regardless of whether it is a first, second or foreign language to you.
If you are an overseas qualified teacher and your English in not as good as that, and you do not want to get a qualification, you could follow a refresher course for teachers. These courses help you upgrade your skills and may offer you the chance to improve your English.