Mukul Roy, one of the founding members of the Trinamool Congress (TMC), on Monday announced his decision to quit the party. Within hours of the announcement, the TMC expelled him for six years.“From December 17, 1997, as one of the first signatories to the birth of Trinamool Congress till today… with heavy heart and pain I am telling you that I will send an e-mail and resign from the working committee of the Trinamool Congress,” Mr. Roy, 63, said at a press conference.The Rajya Sabha MP also announced that after the Puja, he will resign as an MP and from the primary membership of the party.A tall leaderTMC secretary general Partha Chatterjee said Mr. Roy was suspended for hampering the progress of the party and promoting his own interests.Mr. Roy, who held the posts of general secretary and vice-president of the party and served as Railway Minister, was one of its tallest leaders. For years, he was the number two in the party, especially when Ms. Banerjee was in the Opposition in the State. He was the key election manager of the party and was often described as the go-to man in Trinamool.Ever since he deposed before the CBI in January 2015 in the Saradha chit fund scam, differences between him and Ms. Banerjee became evident.