Senior Assam Congress leader Ripun Bora joined Trinamul in Calcutta on Sunday.

Asked why he quit the Congress, he cited “infighting” and the “secret understanding” of senior state leaders with the ruling BJP in his state as reasons.

Bora’s decision follows his defeat in the March 31 Rajya Sabha polls as the joint Opposition candidate despite having the numbers. The Congress and the AIUDF accused each other of cross-voting.

Bora is the third senior Congress leader from the Northeast to join Mamata Banerjee’s party that is trying to expand its national footprint.

Last year, Mahila Congress president Sushmita Dev from Assam and former Meghalaya chief minister Mukul Sangma joined Trinamul.

Bora will be the “first pan-Assam face” for Trinamul that formed its state unit in 2010.

In his two-page resignation letter to AICC interim president Sonia Gandhi, Bora said Congress leaders at “different levels are fighting each other for their vested interest” instead of uniting to fight the BJP, “the symbol of communal and divisive forces”.

Bora said he was “pained” to inform Sonia about the “open secret” of a section of senior Assam PCC leaders “maintaining a secret understanding” with the BJP government, “mainly” with chief minister Himanta Biswa Sarma.

He said his “conscience” did not allow him to continue in the Congress where the party’s interest and ideology were being compromised in favour of the BJP for vested interest of few leaders.

Bora, who has been an Assam minister, PCC president and Rajya Sabha member in the past, was associated with the Congress since 1976 when he was a schoolboy.

Trinamul national general secretary Abhishek Banerjee in a tweet welcomed Bora to the fold, calling him “a stalwart and skilled politician”. Abhishek added that he looked forward to “working together for the well-being of our people!”

In the 2021 Assembly polls in Assam, the Congress could win only 29 seats, three more than in 2016.