The ADI qualification process involves three exams, which you must pass in order within a two-year period after passing the first test. You can find detailed information on the official GOV.UK guide to becoming a driving instructor.
Format: This test has two sections:
Attempts: You have an unlimited number of attempts to pass this test.
Format: This practical test takes about one hour and assesses your expert-level driving skills. It includes:
Attempts: You can have a maximum of three attempts. If you fail all three, you must wait two years after passing Part 1 before you can restart the process.
Format: This test evaluates your ability to teach a learner driver effectively during a one-hour lesson. The examiner observes you teaching a pupil on a pre-planned topic.
Attempts: You have a maximum of three attempts.
Beyond passing the tests, successful ADIs are patient, excellent communicators, and have strong time-management skills. After passing all three parts, you must register with the DVSA within one year to legally charge for driving lessons.
Your registration must be renewed every four years, which includes another DBS check and a standards check to ensure you maintain your teaching abilities.