You can learn to drive anytime as long as it is not on a public road. Many wealthy people allow their offsprings to drive all over their estates e.g. the Royals all drove Landrovers and the like well before they took a test.
What you cannot do is get a licence without a theory pass certificate which would then allow you on a public road with all the RTA restrictions one needs.
Thanks for this its a question from my partner. I have been advised by a number of people recently that he cant start his practical driving lessons until he has passed his theory test. I passed my test a number of years ago but I was doing my practical well before I passed my theory.
of course you can learn to drive before you pass your theory test,take no notice of what paul22118 says,apply for your provisional driving licence and then you can book driving lessons,then when you are ready to take the theory test,take it,if you pass,your driving instructor will tell you when he feels you are ready to take the practical test,good luck,but do it properly.
Just to confirm Norman is correct, you can get your provisional and take lessons and practice (with a qualified driver) without taking your theory test, but you must pass the theory before taking your parctical test.