Shillong, Nov 25 (PTI) Twelve of the 17 Congress MLAs in the Meghalaya Assembly on Thursday joined the Trinamool Congress, dealing a body blow to the grand old party in the northeastern state, their leader and former chief minister Mukul Sangma said. He said the decision to shift allegiance to Mamata Banerjee"s party was taken after "exhaustive due diligence and analysis about how best to serve the people. "The decision has been taken with utmost sense of humility, responsibility and commitment towards fulfilling our responsibility to the people, the state and the nation," he told a press conference. In a massive jolt to the main opposition Congress, they had decided to join the TMC in a late night development on Wednesday. The breakaway group had also submitted a list of MLAs crossing over to the TMC to state Assembly Speaker Metbah Lyngdoh and informed him about their decision. The development is a major boost for West Bengal Chief Minister and TMC supremo Mamata Banerjee, who has been trying to expand her party"s footprint beyond her native state. PTI JOP SK SK SK