BSP MLA from Shravasti, Aslam Raini, made an appearance in the state assembly to participate in the marathon session even though the BSP has chosen to stay away from the same.
He is now the eighth opposition legislator to attend the special marathon session.
Aslam Raini is the third BSP lawmaker to revolt against the party's decision to boycott the session.
Earlier on Wednesday evening, BSP MLA Anil Singh and BSP MLC Brijesh Singh Princu attended the session.
A revolt in the BSP ranks is slowly gathering momentum and the entire party unit in Saharanpur district have joined the Bharatiya Janata Party (BJP).
A senior BSP MLA said that there was a possibility of more BSP legislators attending the session.
"Everyone wants to discuss development related to their constituency and this session provides an opportunity for this. It is not very wise to forego this opportunity," he said.
Earlier four legislators from Samajwadi Party had defied the party decision to participate in the session. SP MLA Nitin Agarwal had participated in the debate in the state assembly while, SP MLC Ravi Shankar Singh Pappu remained present in the Vidhan Parishad.
Two SP MLCs, Shatrudha Prakash and Madhukar Jaitley sent their written speeches to the chairman and requested him to make the documents a part of proceedings. The chairman obliged, despite mild protests from BJP members.
The Congress also faced 'betrayal' from its Rae Bareli MLA Aditi Singh who also defied the party decision and gave a speech in the assembly session.
Aditi Singh had remained away from the padyatra which was led by Congress general secretary Priyanka Gandhi Vadra in Lucknow on Wednesday but appeared in the state assembly late on Wednesday evening, to give a speech.
BJP sources, meanwhile, said that the legislators who had refused to toe their party line and had attended the session were likely to join the BJP.
"It is clear that they support the BJP ideology more than their own party. It is a matter of time before they come into our party," said a senior BJP minister on Thursday.
( With inputs from IANS )