Law School

Actus Reus

In criminal cases, the prosecution must prove that the defendant committed an actus reus and had mens rea at the same time.  Actus reus means a guilty act and mens rea means a guilty state of mind.

UNLAWFUL CONDUCT OR RESULT

An actus reus consists of more than just an act. It also consists of whatever circumstances and consequences are required for the offence in question - in other words all the elements of an offence other than the mental element.  Crimes can be divided into two categories:

First, there are conduct crimes where the actus reus is the prohibited conduct itself. For example, the actus reus of the offence of dangerous driving is simply "driving a mechanically propelled vehicle on a road or other public place" (s2 Road Traffic Act 1988). No harm or consequence of that dangerous driving need be established.

The second type are known as result crimes where the actus reus of the offence requires proof that the conduct caused a prohibited result or consequence. For example, the actus reus of the offence of criminal damage is that property belonging to another must be destroyed or damaged (s1(1) Criminal Damage Act 1971).

VOLUNTARY

The accused's conduct must be "voluntary" or "freely willed" if he is to incur liability. It may be involuntary for a variety of reasons:

Automatism occurs where the defendant performs a physical act but is unaware of what he is doing, or is not in control of his actions, because of some external factor, eg, R v Quick [1973] 3 All ER 347, where the defendant took an injection of insulin and had a blackout during which he assaulted the victim.

Sometimes people can respond to something with a spontaneous reflex action over which they have no control.  The classic example is that given in Hill v Baxter [1958] 1 All ER 193, of someone being stung by a swarm of bees while driving, and losing control of the car.

The conduct may be involuntary if it is physically forced by someone else, in which case there...