Alleging break down of law and order, dissident Trinamool Congress Lok Sabha member Somen Mitra Friday announced he would quit the party and return to the Congress.
However, the senior leader - a former state Congress president - said he would resign from the Lok Sabha before joining the Congress.
"Congress is my mother party. I made a mistake by joining the Trinamool. I have realised it. I want to undo the mistake by rejoining the Congress," said Mitra, who represents the Diamond Harbour constituency in the Lok Sabha.
Mitra said to adhere to ethics, he would not join the Congress while remaining a Trinamool member of parliament.
"So, I will first resign from the Lok Sabha," said Mitra, while opening a Kali Puja in central Kolkata.
Mitra regretted there was a break down of law and order in the state under the Trinamool regime.
"The people's safety issues have remained as they were during the Left Front's misrule," he said.
Mitra, a one time arch-enemy of Trinamool chief and Chief Minister Mamata Banerjee - when both were in the Congress - is regarded as the prime reason for Banerjee's decision to leave the Congress and float another party in 1997.
Later, the arch-rivals turned friends when Mitra joined the Trinamool in 2008, and a year later got elected as an MP on a party ticket.
However, Mitra, used to a position of eminence in the state Congress organisation for decades, never got much importance in the Trinamool. That was not acceptable to the veteran leader.
In August this year, at a blood donation camp, three Trinamool MPs - Shatabdi Roy, Tapas Pal and Kunal Ghosh - lashed out against the party in Mitra's presence.
Though Roy and Pal's rebellion proved brief, and they apologised and made up with the Trinamool leadership, Ghosh has been suspended.
Mitra's wife Shikha, a Trinamool MLA, who had first raised the banner of revolt, has already been put under suspension.
