The statement seems at first glance to offer a much generalised and often contested view of the separation of powers embodied in constitutional theory. That is to say that Parliament makes laws and the judiciary as slaves to the rules, should simply apply them to a particular case. This perhaps is what 'ought' to happen, according to the fundamental nature of rules and the impression that word 'rule' renders; i.e. that following a particular pattern cannot lead you astray. However the broader implications of this narrow position is that judge's decisions are straightforward and mechanistic in appearance, which as we shall see in the operation of precedent and of statutory interpretation, could not be further from the truth.
The obvious starting point for this piece of writing is to state that the rules governing statutory interpretation and precedent 'should' be foolproof. After all, anything contrary to this would call into question Parliamentary Sovereignty and it's competence in performing its legislative functions.
But to submit to the assumption that judges adjudicate only according to the rules leaves us open to much criticism.
However practical and appealing, an approach of simply looking up the law and applying it, may be, it is important to understand that there are no fixed rules of law written in stone, like modern day commandments, which judges can simply draw authority from, and prescribe to a legal problem. Legal rules are composed by men and thus by their most fundamental orthodox, are flawed in some way due to man's imperfectness. I.e. no matter how elaborately it is phrased, no legislator can hope to create a rule to cater for every possible situation arising for future consideration, and legislate to facilitate it. Even if they could, constraints upon draftsmen's time amongst other factors such as the legal compatibility...