In criminal law and in the law of tort, recklessness may be defined as the state of mind where a person deliberately and unjustifiably pursues a course of action while consciously disregarding any risks flowing from such action. Recklessness is less culpable than malice, but is more blameworthy than carelessness.

Mens rea and actus reus To commit a criminal offence of ordinary liability (as opposed to strict liability) the prosecution must show both the actus reus (guilty act) and mens rea (guilty mind). A person cannot be guilty of an offence for his actions alone; there must also be the requisite intention, knowledge, recklessness, or criminal negligence at the relevant time. In the case of negligence, however, the mens rea is implied.

Criminal law recognizes recklessness as one of four main classes of mental state constituting mens rea elements to establish liability, namely: Intention: intending the action; foreseeing the result; desiring the result: e.g. murder. Knowledge: knowing of the falsity or wrongfulness of one's actions or knowledge of a risk that a prohibited result is likely to occur but proceeding anyway. This also includes wilful blindness in most jurisdictions, and recklessness in some others. An example would be offenses involving possession: the accused must have controlled the item and knew that it was contraband. Wilful blindness: having a subjective awareness that a risk could exist (but not necessarily full knowledge) but proceeding without making more inquiries, e.g. a person is asked to bring a suitcase across a border: the person may not know that the suitcase contains drugs but has some suspicions (the person may think the suitcase could contain large sums of money) and, without ever asking or checking what's inside, bringing the suitcase across the border. Recklessness: willingly taking an initial action that a reasonable person would know will likely lead to the actus reus being committed, e.g. drinking alcohol and then driving as a result of automation due to intoxication. Carelessness (also known as negligence): failing to exercise due diligence to prevent the actus reus that caused the harm from occurring – rarely used in criminal law, often encountered in regulatory offenses (e.g. careless driving) or in the civil law tort of negligence – these are known as strict liability offenses.

The tests for any mens rea element relies on an assessment of whether the accused had foresight of the prohibited consequences and desired to cause those consequences to occur. The three types of test are: subjective where the court attempts to establish what the accused was actually thinking at the time the actus reus was caused; objective where the court imputes mens rea elements on the basis that a reasonable person with the same general knowledge and abilities as the accused would have had those elements, (although R v Gemmell and Richards deprecated this in England and Wales);R v Gemmell and Richards or hybrid, i.e. the test is both subjective and objective

The most culpable mens rea elements will have both foresight and desire on a subjective basis.

A subjective test is applied to offenses requiring intent, knowledge or wilful blindness.

For recklessness, a subjective test is applied to determine whether accused wilfully took an initial action that is inherently risky (such as drinking alcohol) but an objective test is applied to determine whether the commission of the actus reus could be foreseen (by a reasonable person).

For carelessness, once the prosecution proved the acteus reus, the defendant must prove that they exercised all the care a reasonable person would to prevent the actus reus from occurring.

Recklessness shows less culpability than intention, but more culpability than criminal negligence.Cases and Materials on Criminal Law - 10th ed. - Elliot & Wood

There are also absolute liability offenses such as speeding. These do not require a guilty mind and due diligence is not a defense but a person cannot be imprisoned for an absolute liability offense.

Recklessness usually arises when an accused should be aware of the potentially adverse consequences to the planned actions, but has gone ahead anyway, exposing a particular individual or unknown victim to the risk of suffering the foreseen harm but not actually desiring that the victim be hurt. The accused is a social danger because they gamble with the safety of others, and, unless they exercised all possible due diligence, the fact they might have acted to try to avoid the injury from occurring is relevant only to mitigate the sentence. Note that gross criminal negligence represents such a serious failure to foresee that in any other person, it would have been recklessness.

A statutorily defined offence will be presumed to require mens rea, even if the Act is silent on the issue.Sweet v Parsley

Criminal systems of the civil law tradition distinguish between intention in the broad sense (dolus directus and dolus eventualis), and negligence. Negligence does not carry criminal responsibility unless a particular crime provides for its punishment.Dörmann, Doswald-Beck and Kolb, Elements of War Crimes, 491Kaiser, Leistungsstörungen, 333

United States Black's Law Dictionary defines recklessness in American law as "Conduct whereby the actor does not desire harmful consequence but ... foresees the possibility and consciously takes the risk", or alternatively as "a state of mind in which a person does not care about the consequences of his or her actions".Black's Law Dictionary 1053 (Bryan A. Garner ed., 8th ed. abr. 2005). In American courts, like English courts, a wrongdoer is found guilty of recklessness based upon the subjective test rule, where the accused must have had the same reasonable knowledge or ability to know the circumstances surrounding the incident in order to be found guilty of recklessness.

In American tort law, recklessness of the tortfeasor can cause the plaintiff to be entitled to punitive damages. Although there is no difference in the quantity of punitive damages awarded for recklessness rather than malice (that is, a plaintiff does not get more punitive damages for establishing malice than he would for establishing recklessness), plaintiffs may still desire to prove maliciousness because, in American bankruptcy law, debts incurred through willful and malicious injuries cannot be discharged in bankruptcy, but debts incurred through recklessness can.

England and Wales The modern definition of recklessness has developed from R v Cunningham 2 QB 396 in which the definition of 'maliciously' for the purposes of the Offences against the Person Act 1861 was held to require a subjective rather than objective test when a man released gas from the mains while attempting to steal money from the pay-meter. As a result, the gas leaked into the house next door, and partially asphyxiated the man's mother-in-law.

The Court of Criminal Appeal reversed the conviction by the trial judge because "maliciously" was read to mean that the result was a reasonably foreseeable consequence of the defendant's actions, saying:

This type of recklessness is called "Cunningham recklessness".Ormerod, David. Smith and Hogan's Criminal Law. Thirteenth Edition. Oxford University Press. 2011. Pages 118 and 119.

The current test in England and Wales is thus one of subjective recklessness, as reaffirmed by the House of Lords in R v G .R v G 3 WLR 1060

R v Caldwell and R v Lawrence In R v Caldwell AC 341 a new definition of recklessness was adopted.

In late 1979, Caldwell, a disgruntled former hotel employee who had recently been fired by his boss, got very drunk one night and decided to set fire to his former employer's hotel, intending to damage the property. When he set the blaze there were ten guests asleep inside the hotel, and though the fire was extinguished quickly, Caldwell was charged not only with arson, contrary to section 1(1) of the Criminal Damage Act 1971 (to which he pleaded guilty), but with the more serious charge of arson with intent to endanger human life, contrary to section 1(2) of that Act.

Caldwell was convicted under section 1(2), which requires that the defendant shall:

The House of Lords was mainly concerned with the extent to which self-induced drunkenness could be a defence to offences of specific intent and basic intent, the latter encompassing recklessness. The Lords ultimately ruled that self-induced intoxication could be a defence to specific intent, but not to basic intent, i.e. recklessness.

The discussion of recklessness in this case tends to be largely obiter dicta. However Lord Diplock said at 354F that it would be proper to direct a jury that a defendant charged with an offence under section 1(1) of the Criminal Damage Act 1971 is "reckless as to whether or not any property would be destroyed or damaged" if:

To that extent, the test is one of obviousness, i.e. if it would have been obvious to the reasonable person, the defendant will be punished for failing to foresee it.

The decision in Caldwell was followed in R v Lawrence AC 510R v Lawrence AC 510, 2 WLR 524, 73 Cr App R 1, 1 All ER 974, RTR 217, Crim LR 409, HL, reversing 71 Cr App R 291 in which the defendant was charged with the offence of causing death by reckless driving contrary to section 1 of the Road Traffic Act 1972. Following his speech in Caldwell at 354C, Lord Diplock said at 526E:

Archbold Criminal Pleading, Evidence and Practice, 1999, para 17–52 et seq., refers to this definition of recklessness as "Caldwell/Lawrence recklessness", and at para 17–57 as "Diplock recklessness" and at para 17–56 as the "Caldwell test".

This form of recklessness is also called "objective recklessness".Ormerod, David. Smith and Hogan's Criminal Law. Oxford University Press. 13th ed. 2011. p. 121.

In Elliot v C (a minor)Elliot v C (a minor) (1983) 77 Cr App R 103, 1 WLR 939, 2 All ER 1055, Crim LR 616, DC a 14-year-old schoolgirl of low intelligence, who was tired and hungry, inadvertently burned down a garden shed. It was accepted that she did not foresee the risk of fire, and that she had not considered the possible consequences of her action. The court reluctantly followed Caldwell. It held that a defendant is reckless as to whether property is destroyed if he or she fails to give any thought to the possibility that there is a risk that property will be destroyed that would be obvious to a reasonably prudent person, even though that risk would not have been obvious to the defendant (by reason of age or lack of experience or understanding) if he had given any thought to the possibility that there was risk that property would be destroyed.

The focus of this test is the nature of the defendant's conduct rather than his mental state and it became the subject of major criticism. For example, how was the direction to apply to the defendant who had considered the risk and only continued to act after deciding (wrongly as it would later appear) that no risk existed? See Chief Constable of Avon and Somerset v Shimmen 84 Cr App R 7, Crim LR 800, DC and R v Merrick 1 Cr App R 130, CA.