Under Article 145(3), “any case involving a substantial question of law as to the interpretation of the Constitution” must be decided by a Bench of at least five judges. Such a Bench is called a Constitution Bench.
However, in several cases, constitutional issues have been decided by smaller Benches as well.
A matter can be referred to a larger Bench only by judicial order. But a 13-judge Bench to reconsider the famous Kesavananda Bharati judgment was initially constituted without a judicial order of reference and had to be dissolved after two days of the tense hearing.
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