4.— In this Part—

“agreement” means an agreement mentioned in section 5;

“certificate” means a certificate issued by the Minister under section 6;

“contractor” has the meaning assigned to it by section 5;

“employment” includes employment under a contract for services, and cognate words shall be construed accordingly;

“prisoner custody officer” means a person—

(a) in respect of whom a certificate under section 6 is in force, and

(b) who is, for the time being, in the employment of a contractor;

“prisoner escort services” has the meaning assigned to it by section 5.