He was welcomed in the party amid a special program at the CPN-Maoist party office, Buddhanagar on Friday.
The UCPN (Maoist) has betrayed people´s aspirations by committing a series of mistakes, Biswakarma said clarifying his decision.
"The responsibility of concluding long-stalled revolution and establish new people´s government now rests on CPN-Maoist," Biswakarma said.
Related story
RSSP candidate defects to UCPN (Maoist)
