Defining ‘criminal law’ and ‘crime’
Jeremy Bentham once described how crimes operate with an analogy:
When your dog does anything you want to break him of, you wait till he does it and then beat him. This is the way you make laws for your dog, and this is the way judges make laws for you and me.
The criminal law seeks to punish unwanted behaviour. Made up of thousands of laws (known as ‘crimes’ or ‘criminal offences’), the criminal law can be distinguished from that of tort law or contract law by its safeguarded procedures (different courts, different burden of proof, different consequences). According to Simester and Sullivan, there are three functions of criminal law: to criminalise unacceptable behaviour; to convict offenders for committing crimes and then to punish those offenders. This state-enforced system of threats is very different to the individually enforced civil law.
Crimes are based on a number of different principles, as illustrated by Ashworth and Horder. The harm principle suggests that behaviour should be criminalised if it risks harming others (such as murder); the welfare principle suggests that behaviour should be criminalised if it could damage the wider community (such as not paying taxes), and the minimalist principle suggests that behaviour should only be criminalised if there is no better way to address the behaviour in question.
Crimes should not be said to be based on morals, as this would lead to questions such as ‘whose morals’ and ‘what moral standard’, however there is no doubt that the criminal law often attempts to reflect what is acceptable and what is not in society. This is best illustrated by sexual offences. John Stuart Mill once suggested that betting should be considered as morally wrong, but not criminally wrong, for example.
Sources of criminal law
In Jeremy Bentham’s analogy (above), there is the suggestion that judges make criminal law: they exclusively did so in the 18th century. However, today, the UK’s democratic Parliament has the exclusive right to create new criminal law. Knuller v DPP  was the first step towards this transition, preventing new offences from being recognised by judges. The case did not prevent the recognition of offences forgotten about for centuries, however. Secondly, in DPP v Withers , Lord Diplock stated that if it takes several days to work out whether a ‘forgotten about’ crime is a crime at all, it should not be recognised in the interest of the prospective certainty of the law. The final step in handing exclusivity to Parliament came in R v Rimmington , which required that criminal offences were not to be put to unorthodox uses by judges.
Today, wherever Parliament has intervened in creating a criminal offence, its crime should be preferred over any judge-made alternative.
Ashworth (above) is an advocate of the minimalist principle, so suggests that the criminal law should only be used as a last resort: a person should only be labelled as a criminal if they have committed a serious wrong. It is said that behaviour should only be criminalised if: it is serious, there is no other way to remedy it, it is enforceable, it is clearly prescribed and it has a justifiable penalty. Of course, this is not how it works in practice.
Overcriminalisation is usually caused in two ways: by regulatory offences and with haphazard intervention by Parliament. Often, crimes represent regulatory offences (such as using a mobile phone while driving), where there is no social condemnation involved, but the state has no better way express its dissatisfaction. As we have no system of ‘administrative’ law, a regulatory offender is classed as a criminal, which many would deem unacceptable. Haphazard intervention by Parliament is usually caused by political pressure. A good example is the Legal Aid, Sentencing and Punishment of Offenders Act 2014, where section 144 makes it an offence for a trespasser, who entered a building as a trespasser and knew or ought to have known he was a trespasser, to live or intend to live in that property for any period of time. Whilst the section is correctly aimed at squatters, the BBC noted that the crime made it no easier for landlords to evict squatters than the previous law. The crime merely gave the appearance that the coalition government was doing something to help landlords. Ashworth said that squatting was addressed as it was easier than a variety of other reforms requested by the Law Commission at the time.
Overcriminalisation could be described as the abuse of criminal law, from which citizens are not protected. Citizens may only protect themselves from legislation in front of the Council of Europe or the European Union, as a result of the doctrine of parliamentary sovereignty, and this perhaps highlights a major flaw within our criminal law system. One way of solving this problem would be to create a criminal code, replacing both the common law and statute entirely, to create a unified set of laws governing behaviour which is classed as criminal. Though proposals for such radical reform by the Law Commission, on several occasions, have been rejected.