We should also see the case of Airedale NHS Trust v Bland14. The House of Lord in this case had to deal with the issue of the duty on doctors to continue to treat a patient in persistent vegetative state for whom there was no prospect of a recovery of any degree of consciousness. The House of Lord dismissed the appeal and viewed the proposed conduct leading to victim's death by discontinuing life support and medical support, as being in nature of an omission, not an act. Lord Goff stated that: "It is true that it may be difficult to describe what the doctor actually does as an omission …
In each case, the doctor is simply allowing his patient to die in the sense that he is desisting from taking a step which might, in certain circumstances, prevent his patient from dying as a result of a pre-existing condition; and as a matter of general principle an omission such as this will not be unlawful unless it constitutes a breach of duty to the patient. " 14  AC 789 Differentiation between Act and Omission in Criminal Law Literally, we understand that an act is an "active" conduct while an omission is an "passive" one.
Most crimes do not include the specific word "act" in their definition. Instead, words are used which imply actions but do not necessarily exclude omissions. Therefore, it may not be easy to distinguish the concepts of an act and omissions in criminal law. For example, a person who engages in a deception to obtain property, or who causes grievous bodily injury, usually does so by an act or series of acts, but neither of these words inevitably excludes the possibility of an omission. Therefore, an omission to act in such circumstances may also convict to a crime.
In Miller, Lord Diplock took a view that much of the apparent difficulty of fitting liability for omissions into the traditional analysis of the actus reus would disappear if a less rigid phrase, such as "course of conduct", were use instead: "it is the use of the expression "actus reus" that is liable to mislead, since it suggests that some positive act on the part of the accused in needed to make him guilty of a crime and that a failure or omission to act is insufficient to give rise to criminal liability…
the habit of lawyers to talk of "actus reus", suggestive as it is of action rather than inaction, is responsible for any erroneous notion that failure to act cannot give rise to criminal liability in English law. " On the other hand, it was held that in Lowe15, manslaughter was held to require proof of an act and it may not be possible to commit an attempt by an omission because s. 1 of Criminal Attempts Act 1981 requires "an act more than merely preparatory".
Moreover, the court held that the words "does acts" in the Protection From Eviction Act 1977 in Ahmad16 could not be satisfied by a failure to do things, i. e. an omission. There are doubts that whether the offences of assault and battery could be simply committed by an omission. 15  QB 702 16  The rationale behind the above is that a mere omission itself does not constitute to actus reus, i. e. no criminal liability. As illustrated in the above, an omission may not satisfy the voluntariness requirement of actus reus or the causation requirement.
Further, as discussed in the previous chapter of the characteristics of omission in criminal law, it is understood that criminal liability will not be established unless there is a special legal duty owed to the victim, no matter it is statutory or contractual. However, the duty concept is unnecessary to criminal offences committed by acts, i. e. no need to prove whether there is a duty or relationship between the accused and victim when the former killed the latter by a knife. To understand more whether criminal liability can be established by an omission in certain occasion, the following cases have been reviewed.
In Fagan17, D had accidentally drove onto a policeman's foot and then, for a short time, refused to drive off. All the judges thought that the offences could not be committed by an omission but majority of the majority held that there was continuing act of keeping the car on the foot. In contrast, the court in DPP v K (a minor)18 appears to have assumed that the accused failure to clear acid out of a dryer which he had earlier thrown it was sufficient for liability for an assault occasioning actual bodily injury under s. 47 OAPA19 when victim's face was scarred when using it.
In Santana-Bermudez, it is possible to describe the defendant's conduct in this case in terms of either an act or omission. When he put the needles in his pocket, he did an act which created a risk for anyone who should thereafter put a hand into the pocket. When he gave an assurance to victim that there were no more needles, he did a further act with mens rea. Even if the first act might be relevant only on the "continuing act" doctrine applied in Fagan, the second act could be regarded as one for the consequences of which he was causally responsible.
Offences Against the Person Act 1869 As a result, differentiation between act and omission may not be easily defined as imagine. In some situations, a conviction of criminal offence could be arisen by either an act or omission. Conclusion Although it is the general rule that criminal liability will not arise for a mere omission, there are exceptions apply.
These exceptions include the statutory duties, the contractual duties, duty arising from special relation of care, duty of a public office, assumption of responsibility and the duty from creation of danger. Beside the active/passive concept of act and omission, we could basically distinguish them by using different approaches, including the duty between accused/victim. However, having reviewed several court decisions, criminal offence may be arose by either committing a prohibited act or an omission. This leads to difficulties in judging the cases as they are all open to the decision of the judges.