Thakur, a Bahujan Vikas Aghadi MLA, was in his car when it was stopped for speeding at 101 kmph on the Bandra Worli Sealink where the permissible limit is 50 kmph.
Thakur moved a breach of privilege notice against Suryavanshi in the assembly.
Suryavanshi, who went to the assembly — to apologise — was cornered by Thakur and legislators Ram Kadam (MNS), Pradeep Jaiswal (independent), Jaikumar Rawal (BJP), Rajan Salvi (Shiv Sena) and others when he came out.
Thakur and Kadam denied beating up Suryavanshi.
Following the assault, speaker Dilip Walse-Patil apologised to the people of Maharashtra, police force and the legislature, and promised a probe.
Chief minister Prithviraj Chavan termed the assault reprehensible. “The video footage is being screened and the speaker will announce his ruling by tomorrow.”
Sources said the legislators could be suspended from the assembly on Wednesday.