Roy used a Bengali slang to describe opposition CPI(M) as a party that had lost its spine and gone to hell.
"When a spine of a person gets broken, he has to go for a plaster and take bed rest for at least three years. The spine of the CPI(M) has been broken.
"I know that CPI(M) doesn't believe in religion but I would still say one thing for those CPI(M) leaders who believe (in religion) that CPI(M) has gone to hell and there is no way they can come back from there."
The remark has drawn criticism from a section of the society including political leaders as it came from Roy, who is known as an erudite politician.
"I am really astonished that such words have been used by Saugata da. He had been always different from others," BJP state president Rahul Sinha said.
"I don't know why he used such words. Saugata da has not been like other Trinamool leaders," state Congress leader Arunava Ghosh said.
Theatre personality Kaushik Sen said, "I was surprised. I knew even his political opponents addressed him with dignity."
Roy's comments came days after Trinamool leader and minister Jyotipriya Mullick's comparison of CPI(M) with a cobra and asking party workers to treat the Left supporters like snakes sneaking into one's room.