The High Court has quashed the decision to destroy a dog for attacking a person because of apprehended bias on the part of a Council officer involved in the decision making process. The case highlights the ability of persons to successfully challenge decisions that fail to abide by the principles of natural justice and the need to ensure decision makers act with impartiality and avoid bias.

Key issues

Judicial review allows persons to challenge decisions on the basis that they have been denied natural justice in the decision making process. One of the requirements of natural justice is that the decision maker be impartial and free from actual or apprehended bias. This raises the following key issues for decision making:

  1. A decision maker, whether acting individually or as part of a multi-member body, must avoid any apprehension of bias. In relation to decisions involving more than one person, bias by any person involved in the decision making process may result in the decision being invalid. This is the case even if the person held to be biased is not the formal or final decision maker.  
  2. The involvement of an investigator or prosecutor in deciding a matter will generally result in an invalid decision. This is irrespective of the actual role or conduct of the person in the decision.  
  3. State agencies, local governments and other relevant decision makers need to ensure the clear separation of roles and responsibilities of officers.


In Isbester v Knox City Council [2015] HCA 20, the High Court considered an appeal from the Victorian Court of Appeal against an application to set aside a decision of the Knox City Council (Council) to order the destruction of a dog under the Domestic Animals Act 1994 (Vic) (Act).

The owner of the dog had been convicted in the Magistrates Court of an offence under the Act on a charge brought by the Council that the owner’s dog had attacked a person and caused serious injury. The Council subsequently convened a panel under the Act to determine the fate of the dog.

The panel was comprised of three Council officers and included the Council officer who was responsible for the prosecution of the dog owner in the Magistrates Court. The panel considered the matter and the chair of the panel (who was not the Council officer involved in the prosecution) determined that the dog should be destroyed.

The dog owner sought judicial review of the Council’s decision in the Victorian Supreme Court on a number of grounds which were rejected by the Supreme Court. The dog owner then appealed to the Court of Appeal on the limited ground of apprehended bias which was dismissed. By grant of special leave, the dog owner then appealed to the High Court.

The central issue before the High Court was whether the panel’s decision to destroy the dog should be quashed because of the involvement of a panel member in both the prosecution of charges against the dog owner in the Magistrates Court and decision of the panel as to the fate of the dog.

Apprehended bias

The legal test for apprehended bias is whether a fair-minded observer might reasonably apprehend that the person in question might not bring an impartial mind to the decision.


The High Court approached the matter by inquiring whether it might reasonably be apprehended that a person in the position of the Council officer would have an interest in the decision which could affect their proper decision making.

The High Court focused on the effect of the interest of the Council officer as the prosecutor in the Magistrates Court on the panel hearing. The Court cited a range of authority that it was contrary to the rules of natural justice for an accuser to be present as a member of a tribunal hearing the charge promoted by the accuser.

The Council argued that the officer’s interest in the prosecution ended when the proceedings in the Magistrate Court came to an end and that the panel hearing under the Act was a separate and independent process. The High Court however considered that there was a continuing or on-going interest and a line could not be drawn between the Magistrate Court prosecution and panel hearing.

Furthermore, given the Council officer’s active participation in the panel hearing, the High Court considered this was similar in nature to the position of a being a prosecutor.

Personal interest

The High Court then turned to the question of whether the Council officer had a personal interest in the panel decision. The Court held that a ‘personal interest’ in this context is not the kind of interest by which a person will receive some material or other benefit and a view or opinion that is personal to them is sufficient (ie. a personal interest could be the vindication of their opinion that an offence occurred or that a particular penalty should be imposed).

Having found that the Council officer involved in the prosecution had an interest in the outcome of the panel hearing, the High Court held there was an apprehended bias and that this was not overcome by the fact that other panel members were involved in the decision.


The case highlights the importance of ensuring that those who are involved in decision making are capable of bringing an impartial mind to the decision making and that their interest is not incompatible with their decision making.