There are proposals being put forward that could mean that motorway driving for learners may become possible (from 2014). In the meantime, once you’ve passed your driving test, you are permitted to drive, alone, on a motorway straight away!
While, statistically, motorways are the safest roads to drive on, I would thoroughly recommend that new drivers take further training before venturing on one for the first time. This could simply by driving with a parent or trusted friend along a short stretch of motorway and, at the very minimum, reading about motorway driving (see my links page to access a webpage from the AA Driving School). If this is not possible, I would advise that you consider a session with a qualified driving instructor.
I offer a two hour Motorway Driving Session (subject to your location) to newly qualified drivers (although I may suggest an Assessment Session or Refresher Session to people who have not leaned to drive with me).
The two hour course is currently priiced at £55.