You must have had a large goods vehicle (LGV) driving licence for at least 3 years to supervise a learner driver.
You don’t need to take formal training or to be registered to teach someone to drive an LGV.
Register as an instructor voluntarily
You can apply to join the national register of LGV instructors. It’s a voluntary register of instructors, endorsed by the Driver and Vehicle Standards Agency (DVSA).
The national register of LGV instructors has replaced the DVSA voluntary register of LGV instructors.