"Historically, the criminal law has been concerned essentially with prohibiting and punishing positive actions rather than with imposing duties to act and punishing failing to do so. In recent times, however, it has increasingly concerned itself with failing to act. " The above statement states that historically in the past physical actions were punished more than failure to act (Omission) but in recent times things have began to change and we have started to punish more failure to acts, I will now critically discuss this mater further.
In criminal law Omission is a failure to act. For example, it is not usually a crime to stand by and watch a child who has fallen into a river drown. Sometimes, however, there is a duty on a person to act, either because of the terms of a contractual duty, or because he is a parent or guardian of a minor, or because he has voluntarily assumed a duty (e. g. looking after a disabled relative), or through a statutory imposition of such a duty. In such cases, omission may constitute a crime.
When Distinguishing the components elements of a crime there is actus reus and mens rea which are both needed to be found in a crime for some one to be punished. Actus reus is the conduct part of the crime where mens rea is the mental state of mind of the defendant. Many criminal offences need proof that the accused performed a voluntary act but there are also some offences that can be committed by an act of omission where one has failed to act; also the defendant can be convicted in respect of another's actions. In most cases a person is not held liable for simply failing to act unless there is a duty to do so?
In criminal law, at common law, there was no duty of care owed to other people. The traditional view was taken from the example of watching a person drown in shallow water and making no rescue effort, the saying, which comes from this which many commentators use is "Thou shalt not kill but needst not strive, officiously, to keep another alive. " So when the courts will look at the case of omission they will look at statutes that explicitly state that actus reus consists of any relevant "act of omission" and use the word "cause", as well positively to find if the defendant proactively injured the victim and negatives in that the defendant intentionally failed to act knowingly that this failure would cause the relevant injury.
In the courts the trend has been to use objective test to determine whether in circumstances where there would have been no risk to the accused health or well being, the accused should of taken reasonable action to prevent any injury or death to the victims. The accused would be liable if the victim was a child in a pool with a water depth of 6 inches, or if there was a devise that could be thrown to the victim to help or if the accused was carrying a phone, which could be used to get help.
The law will never punish a person for failure to act if they were to endanger their own life in sacrifice of helping one in need. No matter what the terms of your employment are, an employee can never be required to do more than what is reasonable in all the circumstances. Historically people were not convicted for their omissions: "it is evident that to punish men by law for not rendering to others all the service which it is their [Moral] duty to render would be preposterous"
This was taken from Lord McCauley's Works (Ed. Lady Trevelyan), Vol. VII, p497. Making all moral omissions a crime would create an oppressive society, It should be noted that this differs from other European countries. In France, for example, in 1997 the "paparazzi" at the scene of Dodi al Fayed and Diana, Princess of Wales were convicted with failing to assist a person in danger. An omission in law is where action is not taken which would prevent or reduce the risk of harm or damage to a person or property, where a person has an obligation to act. A policeman in Dytham  QB 722 was found guilty of misconduct whilst acting as an officer of justice, whilst as he was in uniform and on duty he stood by and failed to assist a man who was beaten to death by a doorman of a nightclub.
His omission to act had contravened his statutory obligation to help, which his profession imposed on him. Where a relationship or assumption of care is present, there is an automatic duty to act, so that if an omission to act results in "legally recognised harm", liability may be applied. In Stone and Dobinson , the court of appeal ruled that by assuming duty of care for his sister they were "obliged to summon help or care for the sister when she became infirm". Lord Atkin ruled that a sentence of manslaughter should be applied to the fatalistic omission, especially when it was proven that if help had been attained at the time of her last bathing, two weeks before her death, she would have survived.
A scenario where liability is addressed for an omission is when "an initial inadvertent action results in harm which the defendant later knowingly fails to avert when the opportunity presents itself", represented by the case of R v Miller (James) . The Court of Appeal ruled that a coincidence of mens rea and actus rea is usually fundamental, however, "an unintentional act followed by an intentional act or,in appropriate cases, reckless omission to rectify it or its consequences, could be regarded together as an intentional act".
The sequence of events from Miller's accidental falling asleep with the lit cigarette in his hand, to discovering that the mattress was smouldering, to ignoring the fire hazard, and moving to a next room was considered, by the House of Lords, as one continuous reckless act. Miller was thus found liable for arson due to his omission to rectify the dangerous situation, which he himself had created, as soon as the opportunity arose.