The case of Hill v Baxter concerns the issue of automatism in English law. It sets out reasonably clear guidelines as to when the defence will apply, and when it will not.

Facts
In this case, a man succeeded in driving a substantial distance before having an accident. He was charged with dangerous driving. He could not remember anything between a very early point of the journey and immediately after the accident. It was suggested (and accepted at first instance) that he was not conscious of what he was doing, and "that he was not capable of forming any intention as to his manner of driving." The reason for this is because he succumbed to an unknown illness, and so was not able to control his actions.

Automatism
As dangerous driving under the Road Traffic Act 1930 was an offence of strict liability, a denial of the requisite mens rea would not be enough to exculpate him. He was instead required to rely on the defence of automatism. Lord Goddard CJ ruled that there would be some situations where "the driver would be in such a state of unconsciousness that he could not be said to be driving." This is in effect a denial of actus reus. However, Lord Goddard found on the facts (which he was probably not legally entitled to do) that the accused had simply fallen asleep. As this was something he had substantial control over, being presumed to have been aware that he was tired, he found that he was reckless in continuing to drive, he then quoted Humphreys J in Kay v Butterworth (1945) and resurrected the now famous and hypothetical situation of a swarm of bees attacking the driver, in which case the driver would not have been held liable.

Pearson J agreed on all relevant points of law, but disagreed as to why he should not be convicted. He held that as the defendant had driven a substantial distance without incident, he was clearly "driving with skill", and therefore must have been driving.

Outcome
The prosecution's appeal was allowed, and the case was referred back to the trial judge. The defendant was, however, eventually found guilty.
The judge in this case held that the act or omission that forms the Actus Reus for an offence must be voluntary. This judgement is used as part of the definition of Actus Reus in the Criminal Law A2 Level Law exam in Britain.