The government did a study a number of years ago, and the average amount of hours of driving lessons that people need to pass their driving test is 45 hours of in car tuition with a driving instructor and 20 hours of driving with a friend or family member to boost your driving skills and experience!
The amount of time it takes YOU to pass your driving test will vary depending on a lot of things, like how much effort and time you put into it. Imagine going doing a college course to learn a skill like bricklaying and only turning up for an hour or two a week. How long would it realistically take you to learn how to lay bricks professionally? Driving is the same! The more often you drive with a driving instructor, especially in a busy place like London, the faster you’ll learn and the less skill fade you’ll get in between lessons. Also some people pick up the skill for driving really quickly while others struggle with the multitasking required to learn to drive. One thing I’m a firm believer in, though, is that EVERYBODY can learn to drive! (unless you’re barred from obtaining a licence on, for example, medical grounds).
So the best thing to do is budget or plan for 45 hours, revise as much as possible, immerse yourself in driving so you pick up as much knowledge and information inside and outside of your lessons, watch Youtube videos, read the Highway Code, and sit at the front of the bus and pretend you’re driving. Spot the hazards, signal timing and behaviour of other cars on the road. If you pass your driving test sooner then BONUS! If you take a bit longer then trust your driving instructor and stick with it and remember the why’s of why you need and want a driving license!