Norman is wrong. You cannot.
You must take a CBT course which is a day. You will also have to use 'L' plates and carry no passengers. Your CBT certificate will be valid for 2 years, and within that time you can choose to take your motorbike test, or just use your CBT and stay as a 'learner'. After the 2 years you will have to take your CBT again to validate it for another 2 years and so on.
i am not wrong at all,you can drive a moped with a provisional licence,the fact that you have to take a CBT course is relevent of course,but my answer was right.thank you.