Singh, who was the State Vice President of Congress, joined BJP along with his supporters in the presence of senior saffron party leaders, including state chief and Jammu MP Jugal Kishore Sharma.
Singh said with the "onset of dynastic politics in Congress", all grassroots worker were feeling "suffocated" and "disillusioned."
"The three regions of Jammu and Kashmir and Darhal constituency in particular have been most backward, underdeveloped due to discriminatory policies of the successive state governments," he alleged.
Jugal Kishore Sharma said, "Joining of a grassroot leader of such a high stature is a matter of pride for BJP. Joining of leaders like Thakur Puran Singh will further strengthened the party and contribute in achieving Mission 44+,".
He joined BJP in the presence of party MP and state in charge Avinash Rai Khanna.