[2] The ruling made by the judge or panel of judges must be based on the evidence at hand and the standard binding authorities covering the subject-matter and areas of law cited in or plainly relevant to the dispute (they must be followed).
This means that a precedent will be dealt to (in English and Scottish law known instead as applied to) a case with similar facts, in which a decision can then be distinguished based upon this, or it may be cited with approval but found to be inapplicable on bases reconcilable with the earlier decision's reasoning.
Where a wide new class of distinguished cases is made, such as distinguishing all cases on privity of contract law in the establishment of the court-made tort of negligence or a case turns on too narrow a set of variations in facts ("turns on its own facts") compared to the routinely applicable precedent(s), such decisions are at high risk of being successfully overruled (by higher courts) on the bases respectively that: Balfour v Balfour (1919) and Merritt v Merritt (1970) were cases involving the enforceability of maintenance agreements.
By contrast, in Merritt v Merritt, the judge distinguished Balfour v Balfour, deciding that the facts were materially different in that: (i) the husband and wife were separated and no longer "in amity"; and (ii) the agreement was made after they had separated, and in writing.
In Read v Lyons (1947),[4] (where a munitions worker was injured in a factory explosion), the court distinguished Rylands v Fletcher (1868) because in the present case, even though the defendant factory kept "dangerous things on the land for a non-natural user", there was "no escape".