Senior Trinamool Congress leader Suvendu Adhikari, who has been at odds with the party's leadership, tendered his resignation as the state's transport minister on Friday amid speculations over his next political move.

Adhikari, the face of the Nandigram movement that catapulted Mamata Bannerjee to power in 2011, sent his resignation letter to the chief minister by fax, which he then forwarded to Governor Jagdeep Dhankhar by e-mail.

"I do hereby tender my resignation from my office as Minister. Steps may be taken for its immediate acceptance. I am simultaneously by e-mail this to His Excellency-Governor of West Bengal, for doing the needful at his end," Adhikari said in the resignation letter.

"I thank you for giving me an opportunity to serve the people of the state, which I did all through with a commitment, dedication and sincerity," he added.

On Wednesday, he had resigned as the chairman of the Hooghly River Bridge Commissioners (HRBC).

Adhikari also shunned his Z-category security cover provided by the state government, sources said.

"Today at 1:05 pm a resignation letter of Mr Suvendu Adhikari from office as minister addressed to Hon'ble Chief Minister has been forwarded to me. The issue will be addressed from a constitutional perspective," the governor tweeted.

The Trinamool Congress remained tight-lipped on the development, while the BJP said that the resignation was a reflection of the anger of TMC leaders against the party's top brass.

Sources close to Adhikari, who has not attended state cabinet meetings over the last few months, said that he was unhappy with the organisational rejig, effected a few months ago.

MPs Sougata Roy and Sudip Bandopadhyay were deputed to talk to him and address the grievances, even as he continued to tour the state and lead rallies organised by his supporters but without the TMC's banner, an unusual for the party.

The Telegraph had previously reported that at an event in East Midnapore last week, Suvendu claimed, “I am still a primary, active member of a political party. I am still a member of a cabinet. The chief minister has kept me as a minister…. Political statements cannot be made while being in the party, while remaining a member of the cabinet…. I am the son of the same soil as Ishwar Chandra Vidyasagar. I will never do anything unethical."

Adhikari had provided a hint about his future actions by admitting that there were rajnoitik mawtantawr (differences of political opinion) and bibhed (disintegration), which could lead to bichchhed (separation).

“There are times, once in a while, when there are differences of political opinion, disintegration… from that disintegration, there can be separation. But for as long as one is in that party, in that cabinet… for as long as decision-makers have not thrown you out, or you haven’t quit yourself, till then statements like that cannot be made from such platforms (like these),” he had said.

Speculations over his possible switch to the BJP or creating a political party aligned with the NDA have been doing the rounds for years, intensified by the rise of Mamata’s nephew Abhishek Banerjee in the party as her political successor.

BJP national general secretary Kailash Vijayvargiya, however, declined to comment on speculation that Adhikari was joining his party.

Apart from his home district of East Midnapore, Adhikari has influence over at least 35-40 assembly segments that are in West Midnapore, Bankura, Purulia and Jhargram, and parts of Birbhum -- the tribal-dominated Junglemahal region.

Elections to the 294-member Bengal assembly is likely in April-May next year.