From 2018, learner drivers will be allowed on the motorways, under the supervision of a qualified driving instructor and in a dual control car. This will not apply to learner motorcyclists.
It will be voluntary and carried out at the discretion of the driving instructor, if they believe the learner to be competent at that level. It will not form part of the changes in the new test which comes into effect on the 4th December.
For more info, check out the news section of www.gov.uk.