Before you intend to drive on the public road, for the category of vehicle you intend to drive, there are legal requirements. You must have one of the following:-

A valid provisional driving licence,

A valid full driving licence,

or

A signed, valid International Driving Permit (IDP),

A full Driving Licence issued outside the UK.

You must be at least 17 years old. 

If you are receiving Higher Rate Disability Living Allowance you can begin driving at 16.

Driving Licences are issued by the Driver and Vehicle Licensing Agency. 

A form D1 can be obtained from the Post Office. 

Or apply online at

www.direct.gov.uk/drivinglicence.

The completed forms should be sent to the appropriate office along with the required passport-type photographs.

To obtain a full Licence you must pass a theory test followed by a practical test for the category of vehicle you wish to drive.  

Then you may drive unaccompanied and on a motorway.