Driving Age Rumours - That website says how it was basically rumours, and why it isn't true; the obvious one being that the house of commons haven't even mentioned it.
Edit:In fact when I looked into it, the last plan with driving age limits was to
lower it to 16, however the plan was rejected about 2-3 years ago. Since then no official plans have been given, and no unofficial ones have leaked in any shape.
Also here is the current law in the UK on driving
You cannot start to drive a car until your provisional driving licence has been accepted and in your possession. If you are in receipt of the higher rate of disability, you can start to learn how to drive when you reach your 16th Birthday otherwise you will have to wait until your 17th Birthday.