As stated it is a criminal offence which I think is awkwardly phrased:
“Driving otherwise than in accordance with a driving licence”
Which means that a driver must hold a driving licence and comply with any conditions or restrictions in the licence.
Interestingly, driving while banned from doing so is often viewed much more seriously than driving without ever having had a licence, as it is seen as deliberately disobeying the instructions of a court of law...