The concept of 'basic structure' of the Constitution, as laid down by the Supreme Court, was first propounded in which landmark case? 

The basic structure doctrine was first authoritatively propounded by the Supreme Court in Kesavananda Bharati v. State of Kerala (1973), decided by a 13-judge Constitution Bench. The majority held that while Parliament has wide powers to amend the Constitution under Article 368, it cannot alter the 'basic structure' or essential features of the Constitution. Golaknath (1967) held that Fundamental Rights could not be amended, but the basic structure doctrine per se was not formulated there. Minerva Mills (1980) and I.R. Coelho (2007) further developed and applied the doctrine but did not originate it.