According to party sources, though Trinamool has gained ground in South Bengal, it cannot bag seats in North Bengal, which is a Congress stronghold, and so the party is eyeing potential defectors to create a base there.

According to a senior TMC leader, Chakraborty has recently shown his keenness to join the TMC. “He is waiting for Mamata's signal,” he said.

“I had a talk with Mukul Roy when he recently visited Malda. I also spoke to Mamata. I have proposed that Chakraborty should be in our North Bengal core committee. I will take him to Kolkata on January 22,” said Babla Sarkar, Malda district TMC president.

District leaders said not only in Malda but leaders and workers of Congress in Cooch Behar, North and South Dinajpur are also keen to join the TMC.

“With Priyaranjan Dasmunshi not here, there is a vacuum in North Bengal. Secondly, issues like Singur and Nandigram have made a great impact here and are helping us expand our base here,” added Sarkar.

Meanwhile, Congress leaders are looking forward to the alliance before the polls.

Senior Congress leader Subrata Mukherjee said: “A few leaders switching sides will not have any effect. However, talks are still on for a grand alliance and there have been four meetings between top leaders of both parties. One should see the alliance materialising.”