First you’ll need to apply to the Driver and Vehicle Standards Agency (DVSA) to become an ADI. To do this you’ll need to give details about your current driving licence including any driving offences. You’ll also need a criminal records disclosure number.
You don’t have to have any training before you take the ADI tests but you’re likely to find it very difficult to pass the tests without specialist training. As well as preparing you for the test, the course will teach you about some of the practicalities of being a driving instructor such as managing your diary and retaining your pupils.