This is a way of avoiding having to follow a previous decision because the material facts are different.

Distinguishing is a method which can be used by a judge to avoid having to follow a previous decision which he or she would normally be bound to follow.  The method can be applied if the judge can find that the material facts of the case he or she is deciding are sufficiently different from the previous decision.  

This will enable the judge to make a distinction between the present case and the previous decision which would otherwise form a precedent which the judge must follow.  Unless the judge is able to draw such a distinction the judge would be bound to follow the previous case even if he or she did not agree with the legal reasoning.  The concept of judicial precedent is strictly adhered to.

There  are two cases which are often cited by way of illustration of how distinguishing works.  The cases are Balfour v Balfour (1919) and Merritt v Merritt (1971).  In both cases a wife made a claim against her husband for breach of contract. In Balfour v Balfour the claim failed as it was decided that there was no intention to create legal relations (one of the conditions one would normally expect in order to find that a legally binding agreement existed).  The arrangement was one which was considered to be a domestic arrangement between a husband and a wife. 

In the later case the claim succeeded.  The court in the case of Merritt v Merritt were able to distinguish that there were material differences in the facts from that of Balfour v Balfour.  In the Merritt case the parties were already separated so that the relationship between one family member and another could be seen to be different and more distant. This might explain why the parties decided to put the agreement in writing (which was not the case in Balfour), again suggesting an intention to put the arrangement on a more formal footing. 

Some might also argue that over the period of years between the cases, society's attitude towards the subject of marital breakdown may well have changed and that the court's decision in Merrritt simply needed to be more realistic and reflect the parties' need to protect themselves.