A valid excuse for violating the law is on the basis of an officially induced error of law.  The defence arises where the accused is given advice in error that the accused relies upon in doing the criminal act.
Officially induced error is available as a defence to prevent morally blameless individuals, who believe they are acting in a lawful manner, from being convicted.
The elements that must be proven are:
- The error was one of law or mixed law and fact
- The accused considered the legal consequences of their actions
- The advice obtained came from an appropriate official
- The advice was reasonable in the circumstances
- The advice obtained must be erroneous
- The accused must demonstrate reliance on the official advice
Each element must be proven on a balance of probabilities by the accused.
This is an exception to the principle that ignorance of the law is no excuse.
The defence arises in part out of the overly complex nature of regulation. 
The purpose of the defence is to prevent injustices where the ““state approving conduct with one hand and seeking to bring criminal sanction for that conduct with the other”
A successful application will result in a stay of proceedings.
- R v Jorgensen at 28 to 37
R. v. Jorgensen 1995 CanLII 85 (S.C.C.), (1995), 4 S.C.R. 55
R. v. Halloran, 2010 ONSC 4321
- R v Jorgensen
- R. v. Jorgensen, 1995 CanLII 85 (SCC),  4 S.C.R. 55 at para. 25
Lévis (City) v. Tétreault; Lévis (City) v. 2629-4470 Québec inc., 2006 SCC 12 (CanLII), 2006 SCC 12 at 24
- R v Jorgensen at para 30
- R v Jorgensen