Binay Tamang on Thursday wrote to Prime Minister Narendra Modi, referring to past treaties with neighbouring countries, which involve the Darjeeling hills, Dooars and the Terai, and demanding that those regions be brought under the Union ministry for north eastern states.

The Gorkha Janmukti Morcha leader has marked a copy to chief minister Mamata Banerjee.

Sources close to Tamang said he had raised the issues with the purpose of ensuring development of the Darjeeling hills, Terai and the Dooars.

The treaties highlighted by Tamang include those with Bhutan and Nepal and the manner in which the Darjeeling hills, Dooars and the Terai were “absorbed” into and not technically incorporated in Bengal.

“If we go by the history of Darjeeling and Kalimpong it shows the land east of Teesta (which includes Kalimpong district and Dooars)…..was ceded to the British government by Bhutan through the Treaty of Sinchula signed on November 11, 1865,” Tamang wrote.

The British government issued a proclamation regarding “annexation” of the Dooars on July 4, 1866, he said.

The hill leader said the three regions had only been “absorbed in West Bengal” under the Absorbed Areas Act, 1954.

“Undoubtedly, these areas are not included or annexed in Indian Territory legally and constitutionally, only absorption has been done. This is a great matter of concern for the nation’s security, integrity and sovereignty,” reads the letter.

In the past too, various Darjeeling leaders had highlighted these treaties and absorption act to claim that the hills were not part of Bengal.

“The state government might not be too happy with the new complexities that Tamang is bringing about but he must be doing this to trigger a new debate in hill politics just before Assembly elections,” said an observer. “A lot is at stake for the Tamang camp of the Morcha in the elections.”

The other demand raised by Tamang is cancellation of the Indo-Nepal Peace and Friendship Treaty 1950, which allows for free movement of people from both the countries in each other’s territories.

Tamang has said that the letter has been written to seek “constitutional justice” for the Gorkhas not just in the region but across India. He has, however, not explicitly explained what he means by “constitutional justice”.

The hill leader, however, is clear on his demand for inclusion of the region in the ministry for north eastern states.

“…regions should be brought under the Development of North Eastern Region (DoNER) under the Articles of 2, 3 and 4 of North East Council Act of 1971,” Tamang has stated and justified his demand on the ground that the people of the hills, Dooars and the Terai are facing “the same vagaries of nature and difficulties of life” as people in north eastern states.