He was admitted to the party in the presence of Uttar Pradesh Congress chief Raj Babbar.
Singh lost the assembly polls in 2012 from Mahoba when he contested as a BJP candidate. Earlier, he was a minister in the Mayawati government.
He has been legislator many times. Before joining the BSP, he was with the BJP for a long time. He was jailed in connection with the multi-crore LACFED scam.