Purshottam Dass Tandon And Ors. vs State Of U.P. Lucknow And Ors. on 25 March, 1986
Once exercised it is complete, and results in total deprivation of the State's power to legislate upon 'a law made by Parliament' pursuant to the power surrendered to it by the legislature of two or more States holds a very special position under the Constitution and must be held to prevail over any other State law (T. Rangayya v. State of Andhra Pradesh, AIR 1978 Andh Pra 106 (FB).