Kolkata, May 13 (IANS) Former Lok Sabha speaker and expelled Marxist leader Somnath Chatterjee Friday said the Communist Party of India-Marxist (CPI-M) should start introspecting from "top to bottom" on why the Left Front government was being decimated in West Bengal.

"It seems that people have opted for them (Trinamool). I must congratulate their leader (Mamata Banerjee)," Chatterjee told Times Now channel.

"It is very easy to abuse one party after one setback. Trinamool also faced same kind of setbacks in 2001 and 2006. So please don't find scapegoats. I believe personally, though I am an outsider, that introspection should start from the top to bottom. They should introspect why people are discontented and why the ordinary people deserted them," said Chatterjee.

His comments came amid indications that the Mamata Banerjee-led Trinamool Congress was going to rout the Left Front that had ruled West Bengal for an uninterrupted 34 years.