Hagrama Mohilary's BPF had been dumped by the BJP in last year's BTC polls.
In a boost for the Congress-led coalition before next month's elections in Assam, the Bodoland Peoples' Front or BPF on Saturday announced that it was quitting the alliance headed by the ruling BJP and joining the opposition front.
"To work for Peace, Unity, and Development and to bring a stable government, free from corruption in Assam, the Bodoland Peoples' Front (BPF) has decided to join hands with MAHAJATH. BPF shall no longer maintain friendship or alliance with BJP. In the forthcoming Assam Assembly Election BPF shall work hand to hand with Mahajath," BPF leader Hagrama Mohilary said in a statement on Facebook.
Formed in 2005 in Assam, the Kokrajhar-based BPF had won 12 of the state's 126 seats in the last assembly elections and joined the BJP-led alliance. Before that, it had allied with the Congress twice - making it a part of the winning side for the last three elections.
But late last year, the BJP dumped the BPF and picked up a new partner to gain a majority and rule the Bodoland Territorial Council (BTC), a self-governing body in the Bodo-dominated areas of Assam.
The BPF, which has three ministers in the Sarbananda Sonowal-led coalition government in the state, emerged as the single-largest party in the BTC polls in December, winning 17 seats in the 40-member body.
BJP leader and Union Home Minister Amit Shah, however, congratulated the United People's Party Liberal (UPPL) for winning 12 seats and termed the party an "ally" in his tweet. Mr Sonowal announced that UPPL chief Pramod Boro will be the new Chief Executive Member (CEM) in the BTC.
Earlier this month, Assam Finance Minister Himanta Biswa Sarma made it clear that the ruling BJP will not have any alliance with the BPF in the upcoming assembly polls in the state.
"We have been telling it many times that our alliance with BPF was for five years only and both sides were committed to it. They are still in our government and it is healthy politics," the BJP leader said.
The BJP is currently the single largest party in the 126-member Assam house with 60 MLAs, while its allies Asom Gana Parishad (AGP) and BPF now have 13 and 11 lawmakers respectively. The ruling coalition also has the support of an Independent MLA.
Assam will see three-phased assembly polls from March 27 to April 6 with results on May 2. For the first time, the Congress is not going solo against the BJP. The party has allied with once arch-rival - Badaruddin Ajmal-led AIUDF, a smaller regional outfit - Anchalik Gana Morcha (AGM) and three Left parties.
Turning it into a three-way battle is an alliance of two regional parties born out of the anti-CAA protests in Assam - the Assam Jatiya Parishad (AJP) formed by former members of All Assam Students' Union (AASU) and other civil society groups and the Raijor Dol, formed by the supporters of noted activist Akhil Gogoi who is in jail for over a year on sedition charges over the anti-CAA protests.