To qualify for protection under Section 8(4)(b) of ESTA, an occupier must prove through properly admissible and authenticated evidence that they are permanently unable to supply labour due to disability at the relevant time. Medical certificates constitute hearsay and opinion evidence that must be properly attested, authenticated, and ideally supported by confirmatory affidavits or testimony when there is sufficient time to do so. A fundamental breach under Section 10(1)(c) of ESTA can be established by examining the totality of an occupier's conduct in the social relationship context, including prolonged rent-free occupation after employment termination, threats to the landowner's employees, and circumstances making it practically impossible to remedy the relationship.