65.This section makes carrying on a regulated activity in breach of the general prohibition a criminal offence.  It is a defence for a person to prove that he exercised due diligence and took all reasonable precautions to avoid committing the offence.
66.A person convicted of this offence, which is referred to as an “authorisation offence”, may be subject to a term of imprisonment of up to 2 years if convicted on indictment (6 months on summary conviction) and/or a fine (the current statutory maximum for a fine on summary conviction is £5,000).
Commentary on Sections Part Ii: Regulated and Prohibited Activities Section 23: Contravention of the general prohibition