P Chidambaram
The former finance minister had in 2006 proposed April 2010 as the deadline for implementing GST. He also released a white paper on state-level value-added tax
Vijay Kelkar
Former finance secretary Kelkar is widely credited with being the architect of GST. In 2009, a task force he headed had suggested a comprehensive, nationwide GST to deal with the complex indirect tax structure. The task force, constituted by the 13th Finance Commission, had recommended that all goods and services should be taxed at a single rate of 12%, split as 5% for central GST and 7% for state GST