In his resignation letter to Council Chairman Ganesh Shanker Pandey, Hargovind Singh said that as he had joined BJP he was resigning from the membership of the house.
Singh's term was to end on January 15, 2016.
BSP had moved an application for the disqualification of its MLC Singh.
"The party has moved an application for disqualification of Hargovind Singh under the Anti-Defection Law as he has joined BJP," BSP general secretary and leader of opposition in the Council, Naseemuddin Siddiqui had said.