Once you turn 18, Uk law states that you can leave home without your ‘parents’ or ‘guardians’ permission
However – If you are 16 or 17 and decide that you want to leave home: ideally you do need their official consent. But if you do leave home without their blessing, you are very unlikely to be summoned back home unless you are in grave danger, vulnerable, ie. have a learning disability or serious mental health problem.
The most likely problem that young people face when they fly the nest before the age of 18 is that they will not be legally entitled to a tenancy agreement. Therefore finding a place to live would prove very difficult.
Note: If you are the age of 18 then please consider all your options before eagerly leaving home. If you are desperate to leave due to problems at home then you can ring childline for free: