Finally, it must be fair, just and reasonable to impose a duty of care. In some cases, there are policy reasons why it is not fair, just and reasonable to impose a duty of care so sometimes public authorities are exempt (Hill). However, this does depend on the circumstances as it was fair, just and reasonable to impose a DOC in MPC v Reeves where the police knew he was a suicide risk and he hung himself in his cell. The police had a duty of care to protect the man from self-harm.