The GRC scheme came into effect on 1 June 1988. Prior to that date, all constituencies were Single Member Constituencies (SMCs). Now, the Parliamentary Elections Act (Cap. 218, 2008 Rev. Ed.) ("PEA") states that there must be at least eight SMCs, and the number of MPs to be returned by all GRCs cannot be less than a quarter of the total number of MPs. Within those parameters the total number of SMCs and GRCs in Singapore and their boundaries are not fixed but are decided by the Cabinet, taking into consideration the recommendations of the Electoral Boundaries Review Committee.