Former Goa Chief Minister Luizinho Faleiro on Monday quit the Congress, his party of 40 years, telling Sonia Gandhi in his resignation letter that he saw "absolutely no hope or will to prevent the collapse of the party".
Luizinho Faleiro also said the Congress "is not the same party for which we had sacrificed and fought".
The 70-year-old is widely expected to join the Trinamool Congress and all but announced it as he showered praise on Bengal Chief Minister Mamata Banerjee.
"Mamata Banerjee has given a tough fight to Narendra Modi. The Mamata formula has won in Bengal," Luizinho Faleiro told reporters, asked to confirm that his party switch. Mr Faleiro asserted that he would continue to be a "Congressman of the larger Congress family", implying that he saw the Trinamool as the Congress offshoot best equipped to fight the BJP.
"Among all four Congresses, it is Mamata who has given a tough fight to (Prime Minister Narendra) Modi and their juggernaut," said the former Chief Minister.
In his resignation letter, Mr Faleiro was considerably sullen and dejected as he recalled the Congress's depletion in Goa from the point in 2017 when power was within the party's reach. He blamed the interference of the "AICC (All India Congress Committee) in-charge of Goa" for the Congress not forming a government at the time, without naming Digvijaya Singh.
"Till now, (no one is) being held accountable for the loss of 13 of our MLAs. I see absolutely no hope or even the will to prevent the collapse of the party and change for the better," wrote the veteran.
"The Congress in Goa is not the same party for which we had sacrificed and fought. It is functioning contrary to every ideal and principle of its founding fathers, "said Mr Faleiro, referring to Indira Gandhi, Rajiv Gandhi, Sonia Gandhi and Rahul Gandhi.
The Goa unit of Congress had become a "cruel parody" of what the party stands for, he said. "Led by a coterie of leaders who prioritise personal gain over the responsibility we owe to our people, we have utterly failed to be an effective opposition."
Mr Faleiro's exit underlines the Congress's rapid decline in Goa. Two years ago, 10 of its 15 MLAs quit and joined the BJP.
Parties like the Aam Aadmi Party (AAP) and Trinamool Congress seek to fill the vacuum.
Earlier today, Mr Faleiro said Mamata Banerjee is the only "streetfighter" who can give the BJP a tough fight.
This will be the second prominent defection to the Trinamool after Sushmita Deb's crossover. While Ms Deb has been given a big role in Tripura ahead of elections next year, Mr Faleiro is likely to bolster the Trinamool in Goa. His experience in the north-east, especially in Tripura makes him a valuable acquisition for the Trinamool.
Mr Faleiro was the Congress's in-charge of Tripura for the 2019 national election and could also help the Trinamool in the northeastern state where it is looking to expand its footprint and take on the ruling BJP.
Goa is due to vote next year, along with Uttar Pradesh, Uttarakhand, Punjab, and other states.