Advantages And Disadvantages Of The Literal Rule
Judges are the only persons constitutionally empowered to interpret legislation authoritatively.  As it is their function to interpret legislation, they will also establish legal rules when interpreting statutes in cases heard before them.  Formerly, the dominant approach to statutory interpretation was the 'literal rule', with its gloss known as the 'golden rule' supplemented by the 'mischief rule'.  However, following the recommendations of the Law Commission's report, The Interpretation of Statutes 1969, the 'purposive' approach has been increasingly favoured. Under this approach, a development of the old mischief rule, the courts construe statutes in the light of the overall purpose of the legislation rather than relying solely on the mere text of the statute. 
This essay will outline the advantages and disadvantages of the literal rule and argue that it is not a sensible guide. It seems that a more purposive approach should prevail when the rules of statutory interpretation are compared.
The so-called literal rule was defined by Lord Tindal as, ‘the words themselves alone do…best declare the intention of the lawgiver’. 
A feature of the rule of law is that the law should be both certain and knowable.  The literal rule ensures that ordinary citizens are able to take statutes at their face value.  As Lord Diplock said, ‘the acceptance of the rule of law…requires that a citizen… should be able to know in advance the legal consequences that will flow from [the statute]…the court must give effect to what the words… would reasonably understood to mean by those whose conduct it regulates.’ 
Moreover, if statements by promoters as to the intent of an act were allowed to prevail, this would contravene the constitutional rule that Parliament is 'sovereign only in respect of what it expresses by the words used in the legislation it has passed’.  It is the elected Parliament that must enact new law and the way of securing that the will of elected legislators will triumph is to take the words enacted by their ‘plain’ meaning.  As Lord Scarman asserted, ‘[The HOL] are to be governed not by Parliament's intentions but by Parliament's enactments’. 
The literal rule also guarantees that the doctrine of the separation of powers is upheld. Lord Diplock in Duport Steels Ltd v Sirs  claimed, ‘the British Constitution…is firmly based upon the separation of powers: Parliament makes the laws, the judiciary interprets them’. For judges to ‘fill up the gaps and make sense of the enactment’  would ‘be a naked usurpation of the legislative function under a thin disguise of interpretation’. 
However, these advantages are undermined by the fact that the notion of any ‘literal’ meaning in an enactment is not itself a notion which is incontestable, nor free from any element of value judgments.  Words can bear a meaning other than the more obvious one, therefore judges, albeit to differential degrees, can apply the meaning that they prefer on grounds of policy or principle.  Eskridge is correct when stating that even the strictest adherence to statutory text cannot obliviate altogether the exercise of judicial discretion in hard cases. ‘Courts must choose among various methods of statutory construction based upon their relative, rather than absolute, ability to constrain judicial usurpation of legislative powers.’ 
Disadvantages – the Problem with Language
‘Simple literalism is fundamentally defective, because it proceeds on the false assumption that a word will always have a plain meaning.’  Lord Reid in DPP v Ottewell affirmed that ‘the imprecision of the English language… is such that it is extremely difficult to draft any provision which is not ambiguous in that sense’. 
Even words which might be thought to have an obvious meaning can have numerous meanings as language is inherently equivocal.  Lord Nolan said, ‘a word or phrase [is] fairly open to diverse meanings, [an] example being ‘twelve o’ clock’ which…could equally mean midday or midnight’. 
This supposed rule would even require the literal meaning to be applied whatever the consequences and however unlikely they were to correspond with what Parliament intended. Lord Esher held, ‘if the words of an Act are clear, you must follow them, even though they lead to a manifest absurdity.’ For the court to apply the literal meaning regardless of consequences is contrary to the judicial oath requiring a judge to ‘do right’.  This was especially true in the case of criminal statutes. If they were capable of two meanings, however unreasonable one of those meanings may be, it was applied if favourable to the accused.  R v Harris is an example of this where someone who bit off his victim’s nose was held not guilty of ‘wounding’. 
Problems with other Rules
The golden rule was set out in Mattison v Hart  where it ‘is to give the words used… their plain meaning unless it is manifest from the general scope…of the statute injustice and absurdity would result.’ However, this rule is problematic as Lord Bramwell in Hill v East & the West India Dock Co  stressed, ‘what seems absurd to one man does not seem absurd to another.’ Also, the very existence of the rule was denied by some judges. 
The mischief rule is also problematic in that the mischief is only one consideration which the court will take into account, therefore it may not always be treated as being determinative of the issue.  In Letang v Cooper  , Lord Denning pointed out that identifying the mischief ‘does not help very much, for the simple reason that Parliament may, and often does, decide to do something different to cure the mischief’.
Need for a more Purposive Approach?
Due to the inadequacies of the three above rules, modern judges have begun to look elsewhere for a guiding principle, and hence adopted a ‘purposive approach’.  Legislation may still be concerned with remedying specific ‘mischief’, but much of it is concerned with seeking to promote a positive social, economic and/or political objectives. 
This approach is required when interpreting English legislation in compliance with EU law. Lord Oliver declared in Litster v Forth Dry Dock Co Ltd  , ‘if the legislation can reasonably be construed as to conform to [UK’s] obligations [under the EC Treaty]…a purposive construction will be applied even though…it may involve some departure from the strict and literal application of the words which the legislature has elected to use’.
Similarly, under the HRA 1998, courts are required under s3(1) to ‘read and give effect to’ all legislation in a way which is compatible with rights under the ECHR so far as it is possible to do so. Again, it may not be possible to interpret English legislation to ensure that it is compatible with the Convention by using the traditional rules. 
The technique of simple literalism is seriously defective and no longer characterises the judicial approach to statutory interpretation.  ‘In adopting the purposive approach to statutes, the courts have shown an increased willingness to cooperate in giving effect to legislative polices, in contrast to their earlier tendency to restrict them by appealing to constitutional values embodied in the traditional presumptions.’  Contrary to what is sometimes said, the court does not ‘select’ any one of these many guides and then apply it to the exclusion of the rest. The courts take an overall view, weigh all the interpretative factors that are relevant, and arrive at a balanced conclusion, also known as the global method of statutory interpretation.  As Donaldson J contended, ‘the interpretation of statutes is a craft as much as a science and the judges, as craftsmen, select and apply the appropriate rules as the tools of their trade.’