You normally need to be 17 to learn to drive a car
You can apply for a provisional licence. You can learn to drive a car and take a test at 17.
If you already have a provisional licence to ride a moped, you don’t need to reapply.
If you’re getting Personal Independence Payment (PIP)
You can learn to drive a car and take a test when you’re 16 if you’re getting, or have applied for, the mobility part of PIP.