Barring order
From Mental Health Law Online
When the RMO opposes the nearest relative's request for the patient's discharge he does so by certifying that the patient, if discharged, would be likely to act in a manner dangerous to himself or others. This certificate (usually done on a standard form) is the barring order. This is the only objection to discharge which the RMO can rely upon to bar the discharge.
See Nearest relative page for further details.