Independent controversy rule

In Mactan-Cebu International Airport Authority v. Heirs of Estanislao Miñoza, et. al., the Supreme Court clarified that:
xxx an independent controversy cannot be injected into a suit by intervention, hence, such intervention will not be allowed where it would enlarge the issues in the action and expand the scope of the remedies. It is not proper where there are certain facts giving the intervenor’s case an aspect peculiar to himself and differentiating it clearly from that of the original parties; the proper course is for the would-be intervenor to litigate his claim in a separate suit. Intervention is not intended to change the nature and character of the action itself, or to stop or delay the placid operation of the machinery of the trial. The remedy of intervention is not proper where it will have the effect of retarding the principal suit or delaying the trial of the action. (G.R. No. 186045, 2 February 2011)