What is it?

A defendant seeks to rely on a necessity-type defence when he argues that he should not be convicted of a criminal offence because his conduct was justified, and it was justified because he did more good than harm in acting as he did.

Defences that are not necessity defences

Given this definition, two defences that are often categorised as being instances of an overarching defence of ‘necessity’ actually having nothing to do with necessity, properly understood.

(1) Duress

The defence of duress – which is available to a defendant who acted under the pressure created by the need to avoid death or serious injury to himself or to someone for whom he is responsible – cannot be analysed as a necessity defence because a defendant seeking to raise a defence of duress is not seeking to justify his conduct. Instead he is seeking to excuse his conduct by arguing, in essence, that ‘I know what I did was wrong, but I acted as I did under pressure that would have led a normal person to act in the same way as I did. So it’s unfair to find me guilty of committing an offence here because had you been in the same position as me, you would have done the same as me. So it’s just an arbitrary accident of fate that had led me rather than you to end up being charged with this offence, and we shouldn’t allow arbitrary accidents of fate to determine people’s criminal guilt.’

(2) Self-defence

The defence of self-defence is often analysed as being a form of necessity defence because: (1) a defendant who seeks to rely on the defence of self-defence is seeking to show that his conduct was justified, just as he would be doing if he were seeking to rely on a defence of necessity; and (2) a defendant who seeks to rely on the defence of self-defence will not be allowed to rely on the defence unless he used reasonable force to defend himself given the facts as he believed them to be, just as a defendant who was seeking to rely on a necessity defence would not be allowed to unless he could show that his actions were reasonable, all things considered.

However, the better analysis seems to be that in a self-defence case, the defendant is arguing that his conduct was justified not because he did more good than harm in using force against his attacker, but because his attacker had no right that the defendant not use force against him. For example, suppose that Anna is being raped by David when Anna manages to reach for a knife and stabs David to death. Most people agree that Anna is entitled to be acquitted of murder here: she will be able to take advantage of a defence of self-defence. But that is not because she did more good than harm in stabbing David to death. Whether or not that was the case is irrelevant. Anna’s conduct here was justified because David had no right that Anna not stab him to death, given what he was doing to Anna. By raping Anna, David forfeited the right he would have normally had against her that she not subject him to lethal force.

(Note that this analysis does not work to explain cases like R v Gladstone Williams (1984) where V was not actually attacking D, but D used force against V because she honestly believed V was a threat to her; in such a case, it is hard to say that V had no right that D not use force against him. Gladstone Williams must be explained on some other basis, such as that D’s conduct can be excused. But a problem with this is that in an excuse case, the defendant has to show that his conduct was reasonable, so as to allow the defendant to argue that ‘You would have done the same as me had you been in my position’ – and the effect of Gladstone Williams is to acquit a defendant who has acted on the unreasonable belief that he or she is being attacked.)

Statutory defences that look like necessity defences

There are some statutory defences that, it could be argued, look like forms of necessity defences:

(1) Damage to property

Under s 5(2) of the Criminal Damage Act 1971, a defendant who is charged with causing criminal damage to another’s property will have a defence if he acted as he did in order to protect other property from being damaged, and he acted reasonably in that belief. The classic example where this defence would apply where a fire is raging down a row of houses; the fire services will be authorised to pull down a house in the middle of the row so as to create a fire break and stop the fire spreading any further. By pulling down the house in the middle of the row, the fire fighters have done more good than harm and are entitled to justify their conduct on that basis.

(2) Refugees

Under s 31 of the Immigration and Asylum Act 1999, a defendant who has been charged with committing various offences in order to enter the UK will have a defence if he came to the UK directly from a country ‘where his life or freedom was threatened’ and promptly presented himself to the authorities and made a claim for asylum. A defendant who prevented himself being killed or imprisoned by entering the UK under a false passport, or by smuggling himself across the UK’s borders, will have done more good than harm and is entitled to justify his conduct on that basis.

(3) Crime stoppers

Section 3(1) of the Criminal Law Act 1967 says that ‘A person may use such force as is reasonable in the circumstances in the prevention of crime, or in effecting or assisting in the lawful arrest of offenders or suspected offenders or of persons unlawfully at large.’ Provisions of the Police and Criminal Evidence Act 1984 confer numerous powers on the police to do things that would otherwise be criminal offences, such as stopping and searching someone (s 1), seizing property (s 19), arresting someone (s 24) and detaining someone in custody (Part IV). Such provisions can most easily be explained on the basis that the sort of conduct covered by these provisions is in the public interest and is therefore justified.

Necessity under the common law

It seems that the courts do not accept that a defendant who has been charged with a criminal offence can ever take advantage of a defence of necessity under the common law. So unless some statute provides the defendant with a necessity-type defence, it will not do the defendant any good to plead, ‘In acting as I did, I did more good than harm.’ Such a plea will fall on deaf ears.

This may seem a controversial claim, given the many cases in which the courts have begun to recognise the existence of a general defence of necessity and set out the situations in which such a defence will be available to a defendant. However, in all those cases (except two) the courts consistently run together the defence of necessity with the defence of duress of circumstances. They do this so consistently that when the courts talk of a defendant being allowed to take advantage of a defence of ‘necessity’ it seems that they are really talking about when a defendant will be allowed to take advantage of a defence of duress of circumstances.

Consider, for example, the following quote from Simon Brown J in R v Martin (1989) (driving while disqualified):

‘First, English law does, in extreme circumstances, recognise a defence of necessity. Most commonly this defence arises as duress, that is pressure upon the accused’s will from the wrongful threats or violence of another. Equally, however, it can arise from other objective dangers threatening the accused or others. Arising thus it is conveniently called “duress of circumstances”.

‘Secondly, the defence is available only if, from an objective standpoint, the accused can be said to be acting reasonably and proportionately in order to avoid a threat of death or serious injury.

‘Thirdly, assuming the defence to be open to the accused on his account of the facts, the issue should be left to the jury, who should be directed to determine these two questions: first, was the accused, or may he have been, impelled to act as he did because as a result of what he reasonably believed to be the situation he had good cause to fear that otherwise death or serious physical injury would result? Second, if so, may a sober person of reasonable firmness, sharing the characteristics of the accused, have responded to that situation by acting as the accused acted? If the answer to both those questions was yes, then the jury would acquit: the defence of necessity would have been established.’

This passage was endorsed in R v Abdul-Hussain (1998) (hijacking of plane) as providing ‘the clearest and most authoritative guide to the relevant principles’ as to when a defence of necessity would be available. (Which dictum was in turn approved in R v Shayler (2001) (breach of Official Secrets Act 1989) and R v S (2012) (child abduction).) But it is clear that Simon Brown J was not talking about necessity at all – in the sense in which I have defined that defence – but was rather talking about when a defendant will be able to take advantage of a defence of duress (either duress by threats or duress of circumstances). As we have already observed, duress is not necessity. As Brooke LJ observed in In Re A (2001) (separation of conjoined twins), ‘In cases of pure necessity the actor’s mind is not [as it is in duress cases] irresistibly overborne by external pressures. The claim is that his or her conduct was not harmful because on a choice of two evils the choice of avoiding the greater harm was justified.’

Despite this, the courts have continued to identify the defence of necessity with the defence of duress of circumstances. In R v Conway (1989) (reckless driving), Woolf LJ held that:

‘necessity can only be a defence to a charge of reckless driving where the facts establish “duress of circumstances,”… i.e. where the defendant was constrained by circumstances to drive as he did to avoid death or serious bodily harm to himself or some other person.  …Whether “duress of circumstances” is called “duress” or “necessity” does not matter. What is important is that, whatever it is called, it is subject to the same limitations as [the] “do this or else” species of duress.’

Twelve years on, in R v Shayler (2001, CA), Lord Woolf CJ was still of the same mind. Dismissing arguments that necessity and duress were distinct in that necessity is a justification and duress is an excuse, he said: ‘…the distinction between duress of circumstances and necessity has, correctly, been by and large ignored or blurred by the courts… the law has tended to treat duress of circumstances and necessity as one and the same’ (at [55]).

The two cases that might genuinely be said to have recognised the existence of a defence at necessity under the common law are Gillick v West Norfolk and Wisbech AHA (1986) and In Re A (2001). Let’s look at each of these in turn.

In Gillick, the issue was whether a doctor who prescribed contraception to a girl who under 16 would be guilty of an offence under s 28 of the Sexual Offences Act 1956 of causing or encouraging unlawful sexual intercourse ‘of a girl under the age of sixteen for whom he is responsible’. (Note that this offence was repealed by the Sexual Offences Act 2003, s 10 of which makes it an offence to cause or incite someone who is under 16 to engage in a sexual activity.) The majority (Lords Fraser, Scarman and Bridge) took the view that a doctor may well commit an offence under s 28 if he prescribed contraception to an under 16 year old girl ‘with the intention of facilitating her having unlawful sexual intercourse’, but a doctor could not be said to have such an intention if he was honestly prescribing the contraception ‘for the maintenance or restoration of [the girl’s] health.’ (Both quotes from Lord Scarman’s judgment.) The minority (Lords Templeman and Brandon) disagreed, holding that if a doctor prescribed contraception to a girl who was under 16, he would be ‘promoting, encouraging or facilitating the having of sexual intercourse’ (per Lord Brandon) and as a result would commit an offence under s 28. None of the judgments in Gillick say anything about necessity: they were purely concerned with the question of how s 28 of the 1956 Act should be interpreted. So there is nothing in Gillick that can be said to support the existence of a defence of necessity under the common law.

That leaves In Re A, in which the Court of Appeal had to decide whether it would be lawful to carry out an operation to separate two conjoined twins, Jodie and Mary, even though such an operation would inevitably result in the death of one of the twins, Mary. There was no possibility of arguing that the defence of duress of circumstances could apply to make the operation lawful: (1) duress cannot be excuse murder (a defendant cannot claim ‘you would have done the same as me’ when what he has done is intentionally kill someone else); (2) as Robert Walker LJ observed ‘The doctors are not faced with any threat to themselves, but they are faced with the anxious dilemma of trying to perform their professional duties which they owe to their two infant patients.’ So In Re A provided an excellent test case for whether the Court of Appeal were willing to recognise a defence of necessity independent of a defence of duress of circumstances.

All three judges in the Court of Appeal held that the doctors would not be committing a crime in operating to separate the conjoined twins.

Ward LJ held that the operation would be justified on the grounds of self-defence, as Mary – who was dependent on being supplied with blood from Jodie’s heart to stay alive, with the result that Jodie’s heart was destined to fail if she remained joined to Mary – posed an ‘unjust’ threat to Jodie’s life.

Brooke LJ held that the operation could be justified on the ground of necessity. He held that ‘there are three necessary requirements for the application of the doctrine of necessity: (i) the act is needed to avoid inevitable and irreparable evil; (ii) no more should be done than is reasonably necessary for the purpose to be achieved; (iii) the evil inflicted must not be disproportionate to the evil avoided.’ He thought that all three conditions were satisfied in this case. It is not, however, clear that Brooke LJ thought that satisfying conditions (i) – (iii) would be sufficient to give rise to a defence of necessity. A few paragraphs before setting out these conditions, he held that there were two objections to recognising a defence of necessity in a case where a defendant was charged with committing a criminal offence: (1) that it was beyond the competence of the courts to assess whether the operation would do more good than harm; (2) that allowing a defence of necessity would result in the court authorising someone to act immorally. Brooke LJ thought that neither objection applied In Re A. On (1), it was obvious whether or not the operation would do more good than harm: dealing with this question did not require the courts to put a comparative value on Jodie and Mary’s lives. If the operation were not carried out, both Jodie and Mary would die. If it were carried out, Jodie would live and Mary would die. Given this, it was obvious what was the better option. On (2), it was not clear that carrying out the operation would be an immoral act, so it was not clear that by allowing the operation to be carried out the court would be ‘marking an absolute divorce of law from morality’.

Robert Walker LJ seemed to take the view that the operation did not even approach the threshold of criminality that would require the doctors to rely on a defence to justify or excuse their actions. He held that the doctors carrying out the operation could not be said to have intended to kill Mary (so they would not have the mens rea for murder), and could be said to be acting in Mary’s best interests in carrying out the operation as ‘The operation would give her, even in death, bodily integrity as a human being’ (so they would not be breaching the duty of care they owed Mary as her doctors in carrying out the operation and could not therefore be held guilty of gross negligence manslaughter).

So – of the three judges who decided In Re A, only one (Brooke LJ) rested his decision on the basis that the doctors could take advantage of a defence of necessity which was genuinely distinct from a defence of duress of circumstances. And Brooke LJ’s judgment remains the only English authority that there exists a defence of necessity at common law that is distinct from a defence of duress of circumstances. Given this, it seems fair enough to say that the English law does not currently recognise that a defendant who has been charged with a criminal offence can ever rely on a defence of necessity to justify his conduct in the absence of some specific statutory provision which allows him to raise a necessity-type defence to the charge.

Why are the courts so unwilling to recognise a free-standing defence of necessity?

There seem to be four reasons for the lack of authority in favour of the proposition that a defendant is entitled to be acquitted of a criminal charge if he can show that he did more good than harm in acting as he did.

(1) The definition of offences

There are two ways in which the definition of an offence can exclude a defendant from seeking to rely on a defence of necessity to justify his conduct.

First, the definition of an offence may make it unnecessary for the defendant to rely on a defence of necessity to justify his conduct, because the facts which the defendant might have wanted to rely on as giving him a defence of necessity will also allow him to argue that he does not commit the actus reus of the offence with which he is charged, or that he did not commit the actus reus of the offence with the requisite mens rea. For example, in R v Abdul-Hussain (1998), Rose LJ observed that ‘if Anne Frank had stolen a car to escape from Amsterdam and been charged with theft, the tenets of English law would not have denied her a defence of duress of circumstances, on the ground that she should have waited for the Gestapo’s knock on the door [before attempting to escape in a stolen car].’ But in such a case Anne Frank would not have needed to rely on a defence to avoid being convicted of theft. She would have been able to argue that in the circumstances, her appropriation of the car was not dishonest – with the result that she did not commit the actus reus or mens rea of theft (depending on how you classify the requirement of dishonesty in theft, as going to the actus reus or the mens rea of theft).

Secondly, where an offence has been created under a statute, it might be impossible for the defendant to rely on a defence of necessity to justify his conduct because it will be clear from the definition of the offence that Parliament did not intend such a defendant to be allowed to escape conviction by pleading that his actions were in the public interest. The most obvious example of this is the Official Secrets Act 1989. The Act does not provide any defence to someone who claims that they were acting in the public interest in making public secrets ‘relating to security or intelligence’ that they came across by virtue of their position as ‘a member of the security and intelligence services’ or as a government official who has been notified that they are bound by the Act. Given this, the courts would be flouting the will of Parliament if they were to allow such a defendant a defence of necessity under the common law; and they so ruled in the case of R v Shayler (2003, HL). For similar reasons, the appeal in R v Quayle (2005) – where the defendant attempted to justify their possession of marijuana on the basis of ‘medical necessity’ – was doomed to fail. The Misuse of Drugs Act 1971 provides no defence to those who possess marijuana for medical purposes. Given the extreme likelihood that this was a deliberate decision on the part of Parliament, it would have been a violation of Parliamentary sovereignty for the courts to hold that the defendants in Quayle were entitled to a defence of necessity. It was different in DPP v Pipe (2012), where the defendant was charged with breaking the speed limit when he drove his son – who had broken his leg playing football – to hospital. Allowing him to rely on a defence of necessity (here, a synonym for ‘duress of circumstances’) did not involve the courts in violating the will of Parliament in setting speed limits for motorists. Parliament – or the ministers exercising powers to set speed limits delegated to them by Parliament – could not be expected to have had circumstances such as those in DPP v Pipe in mind in setting speed limits.

(2) Rights

Most common law offences exist to protect individual’s rights that other people not treat them in certain ways (kill them, rape them, take their property, batter them, and so on). The fact that English law recognises that people have rights reflects the individualistic ethos of English law, under which greater priority is placed on protecting the freedom of the individual than the welfare of the community. Rights give people a veto power over what can be done to them in the name of the public interest. In Ronald Dworkin’s vivid phrase, ‘rights are trumps’.

In contrast, the existence of necessity defences reflect a more communitarian ethos, under which greater priority is placed on promoting the welfare or the community than on protecting the freedom of the individual. If ‘I did more good than harm’ were always a defence to being charged with committing a criminal offence, then people would have no rights. All people would have were interests that would be taken into account in determining what the right thing to do would be. So if V’s interests in not being killed by D were outweighed by the community’s interests in seeing that V was killed by D, then the law would permit V to be killed by D. It would not be possible anymore to say that V had a right not to be killed by D because killing V might be allowed, depending on the circumstances.

Of course, if the balance of interests indicated that V should not be killed, then we could say in that situation that V has a right not to be killed by D. But that statement, that V has a right not to be killed by D, would simply represent the conclusion of a chain of reasoning: ‘It would do more harm than good to kill V, so V should not be killed, so V has a right not to be killed by D.’ The statement that V has a right not to be killed by D would not – as it does in a community which adopts an individualistic ethos – form the premise of a chain of reasoning: ‘V has a right not to be killed by D, so it would be wrong for D to kill V even though killing V would, on balance, do more good than harm.’

It follows that so long as English law adopts an individualistic ethos, it cannot recognise the existence of necessity defences to crimes which involve violating an individual’s rights. Recognising the existence of such defences would be fatal to English law’s individualistic ethos, in the same way that kryptonite is fatal to Supeman: they cannot co-exist in the same space. English law could not at one and the same time recognise that people have rights and recognise that a defendant could justify treating someone in a particular way by arguing ‘I did more good than harm.’ It has to be one or the other; not both. Once we grasp this, we can see that arguments about whether the law should recognise a defence of necessity (in the sense that it has been defined in this essay, a justification based on the plea ‘I did more good than harm’) are really debates about whether the law should be influenced by an individualistic ethos or by a communitarian ethos. And the fashionability of communitarian ideas among academics explains why so many academics are in favour of the criminal law recognising a fully-fledged defence of necessity.

(3) Judgment

Even if English law were to adopt a more communitarian ethos – and many people would say that it has been in the process of doing that since the 1970s – the courts would still have good reason to hesitate over whether or not to allow defendants to rely on a necessity defence, at least in cases where they are not excluded from doing so by the terms of the offence with which they have been charged. In a case where a defendant argued ‘My conduct was justified because I did more good than harm’, it will often be very difficult for the courts to judge whether or not the defendant’s argument is made out. The problem is not really that the courts lack the expertise to weigh the goods and harms that were produced by the defendant’s conduct, but more that no one could weigh those goods and harms because no one can tell what those goods and harms are. For example, in R v Dudley and Stephens (1884), the court held that the defendant seaman – who had abandoned ship in the middle of a storm and put to sea in an open boat with a cabin boy – could not justify killing the cabin boy in order to eat his body on the basis that had they not done so, they would have all starved to death. Lord Coleridge CJ pointed out that even if it were the case (which was not actually certain, as they might have been picked up any day by a passing ship; or they might not have been picked up at all, ever) that the people in the open boat had a choice between ‘One of us dies, and the rest of us live’ and ‘We all die’, that could not justify killing the cabin boy as opposed to any of the other people in the boat. Killing the cabin boy could only be justified if that was the least worst option. But:

‘Who is to be the judge of this sort of necessity? By what measure is the comparative value of lives to be measured ? Is it to be strength, or intellect, or what? …In this case the weakest, the youngest, the most unresisting, was chosen. Was it more necessary to kill him than one of the grown men? The answer must be “No”…’

None of us can really tell what the consequences of our actions will be. Given this, asking the courts to determine whether the defendant’s actions did more good than harm is asking them to do the impossible. Even in a case like In Re A, where it seems clear-cut that going ahead with the operation would do more good than harm, it is not impossible to imagine futures where not carrying out the operation would have been the better option: for example, a future where Jodie grew up to become a mass murderer, or a future where Jodie became so depressed at owing her life to the death of her twin that she was never able to function normally or enjoy life. And it is not impossible to imagine twists on those futures that would allow us to say that, in fact, carrying out the operation was actually still the better option, where the tragedies resulting from Jodie’s existence had outcomes that worked to offset the initial suffering involved in those tragedies.

(4) Disorder

The final reason for being cautious about recognising the existence of necessity defences, even in a legal system that is fully committed to adopting a communitarian ethos, is the potential for disorder that the existence of such defences creates. The criminal law will speak with a more uncertain voice, and provide less of a constraint on people’s actions, if people know that their conduct will not be attract a criminal sanction if they can establish that they did more good than harm in acting as they did. This consideration played some part in the decision of the court in R v Dudley and Stephens to deny a necessity defence to the defendants in that case. Lord Coleridge CJ warned of the ‘awful danger’ involved in allowing that ‘the temptation to murder’ could give rise to a defence to a charge of murder:

‘such a principle once admitted might be made the legal cloak for unbridled passion and atrocious crime. There is no safe path for judges to tread but to ascertain the law to the best of their ability and to declare it according to their judgment… [A judge] has no right to declare temptation to be an excuse, though he might himself have yielded to it, nor allow compassion for the criminal to change or weaken in any manner the legal definition of the crime.’

Almost a hundred years later, in Southwark London Borough Council v Williams (1971), Lord Denning MR advanced similar reasons for refusing to find that squatting in abandoned premises could be justified on the grounds of necessity:

‘The doctrine [that private property may be sacrificed to avoid ‘great and imminent danger’] must…be carefully circumscribed. Else necessity would open the door to many an excuse. It was for this reason that it was not admitted in Reg. v. Dudley and Stephens (1884) 14 Q.B.D. 273, where the three shipwrecked sailors, in extreme despair, killed the cabin boy and ate him to save their own lives. They were held guilty of murder. The killing was not justified by necessity. Similarly, when a man, who is starving, enters a house and takes food in order to keep himself alive. Our English law does not admit the defence of necessity. It holds him guilty of larceny. Lord Hale said that “if a person, being under necessity for want of victuals, or clothes, shall upon that account clandestinely, and animo furandi, steal another man’s food, it is felony…”: Hale, Pleas of Crown, i. 54. The reason is because, if hunger were once allowed to be an excuse for stealing, it would open a way through which all kinds of disorder and lawlessness would pass. So here. If homelessness were once admitted as a defence to trespass, no one’s house could be safe. Necessity would open a door which no man could shut. It would not only be those in extreme need who would enter. There would be others who would imagine that they were in need, or would invent a need, so as to gain entry. Each man would say his need was greater than the next man’s. The plea would be an excuse for all sorts of wrongdoing. So the courts must, for the sake of law and order, take a firm stand. They must refuse to admit the plea of necessity to the hungry and the homeless: and trust that their distress will be relieved by the charitable and the good.’

Conclusion

It seems that the current state of law on when a defence of necessity (properly understood as a justification resting on the argument ‘I did more good than harm’) will be available is justified. If necessity-type defences are to be recognised under the law, it would be better if they were created by Parliament, rather than the courts. Giving effect to statutory necessity defences would pose no threat to the doctrine of Parliamentary sovereignty. Moreover, Parliament is in a better position than the courts to judge when acting in a particular way can be justified on the basis that acting in that way did more good than harm, and to set out what factors are to be taken into account in reaching that conclusion. Further, the statutory necessity-type defences are less likely to be abused or misused as their scope should be clearly delineated and understood in advance; something that is not possible when the courts undertake to sketch out on a case-by-case basis when they will permit a defendant to rely on a necessity defence.