A public authority that has acted ultra vires cannot rely on the unlawfulness of its own acts to found a criminal decision. Surprisingly, this issue was considered for the first time in a recent UK Court decision.
The decision helpfully clarifies the status of decisions that are void under public law rules. While only a High Court of Justice decision and unreported in the UK, the case is helpful enough that the New Zealand Administrative Law Reports has taken the unusual step of reporting it (White v South Derbyshire District Council  NZAR 778).
The general principle
The Courts have long recognised that in public law an ultra vires act is void and therefore to be treated as a nullity. This means that it will be treated as never having any legal effect, even if it is not found by a Court to be ultra vires until some time after the act occurred.
There are, however, some instances when an ultra vires act has some legal effect.
The UK case
In White v South Derbyshire District Council the Council had unlawfully granted licences to use land as a caravan site. This was not discovered until after the Whites had acquired the site and the licences. All the parties agreed that the licences had been unlawfully issued, but no agreement was reached as to the consequences and the Whites continued to use the site.
Eventually the Council decided to prosecute. The Whites claimed that the Council could not rely on the unlawfulness of its own actions to base the prosecution.
The Court's decision
The Court confirmed the general principle that an ultra vires act normally has no legal effect. However, the Court looked to a long line of authority which recognises that the act in fact occurred, and other parties may have then acted in reliance on the ultra vires act. In those situations, any parties who acted innocently on the assumption that the ultra vires act was valid are entitled to protection.
The other key point coming from the previous cases is that, even if an action or decision is found ultra vires, the Court has discretion on whether or not to order relief, and over the form of relief.
The Court therefore found that the Council could not prosecute the Whites, as the prosecution relied entirely on the Council's own ultra vires act. There was no evidence that the Whites had any reason to think that the caravan licence was invalid, until the issue was raised by the Council. Even then, the Court held that the appropriate challenge to the licence would be through judicial review (bought by the Mayor or a councillor) rather than criminal proceedings.
The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.