(1)This section applies if it is alleged that a person (“the carrier”) is liable to a penalty under section 32.
(2)It is a defence for the carrier to show that he, or an employee of his who was directly responsible for allowing the clandestine entrant to be concealed, was acting under duress.
(3)It is also a defence for the carrier to show that—
(a)he did not know, and had no reasonable grounds for suspecting, that a clandestine entrant was, or might be, concealed in the transporter;
(b)an effective system for preventing the carriage of clandestine entrants was in operation in relation to the transporter; and
(c)that on the occasion in question the person or persons responsible for operating that system did so properly.
(4)In determining, for the purposes of this section, whether a particular system is effective, regard is to be had to the code of practice issued by the Secretary of State under section 33.
(5)If there are two or more persons responsible for a clandestine entrant, the fact that one or more of them has a defence under subsection (3) does not affect the liability of the others.
(6)But if a person responsible for a clandestine entrant has a defence under subsection (2), the liability of any other person responsible for that entrant is discharged.