New Delhi, April 29: A Constitution amendment bill aimed at ending a nearly seven-decade-old boundary dispute with Bangladesh appears set for introduction in the Lok Sabha next week, although a key state that would have to give up territory has been left out for now.

The bill - which has already been introduced in the Rajya Sabha but awaits consideration and passage - leaves out Assam, apparently in deference to the BJP's state unit.

The Constitution (119th Amendment) Bill, 2013, which the Centre is set to table in the lower House, is aimed at resolving the 67-year-old dispute between India and Bangladesh. If passed, it would enable the neighbours to swap enclaves, end differences over pending adverse possessions and, finally, adjudicate over an un-demarcated land boundary measuring approximately 6.1km.

Enclaves are territories that belong to one country but are entirely surrounded by the other.

The bill, based on a protocol signed by Manmohan Singh when the former Prime Minister visited Bangladesh in September 2011, will entail a constitutional amendment. This means it will have to be ratified by the Lok Sabha and the Rajya Sabha with a two-thirds majority.

Three senior BJP ministers separately informed The Telegraph that in deference to the Assam unit's "political considerations", Bangladesh has been "told" that the state would not forfeit even a small piece of the 250 acres of enclaves within its boundary.

There was no clear word from the ministers on who exactly had broached the issue with Bangladesh and whether India's terms were acceptable to Dhaka.

External affairs ministry officials said it was "unclear" if Bangladesh would consent to leaving Assam out of the constitutional amendment. "The land boundary agreement with Bangladesh is for all enclaves the two countries have inside the other's territory. Once you start picking and choosing, it's a tricky slope," said an official.

A second official hinted that a fresh constitutional amendment could be brought later to incorporate Assam under the agreement to ensure the pact with Bangladesh remained on course.

State elections are due in Assam in 2016, the same year Bengal, Kerala and Tamil Nadu vote, too.

It is learnt that the state BJP plainly told the central leaders that if Assam was "forced" to accede "even an inch", the party could face a backlash after an impressive showing in the Lok Sabha and local body elections. "We have always used Bangladeshi infiltration as a plank to build our political capital. We succeeded to a large extent. Since this bill directly involves land exchange with Bangladesh, it is loaded with emotive implications," an Assam BJP MP said.

A central minister explained that they tried to persuade the Assam leaders to soften their objections, but the clincher was Congress chief minister Tarun Gogoi's "tough talk" against yielding land. "He kept quiet for a long time. But lately, he has begun to make threatening noises that made the state BJP go on the defensive. The leaders emphasised to us that the draft law had to be changed," the minister said.

The ministers claimed Bengal chief minister Mamata Banerjee had agreed to the draft, as had her counterparts in Tripura and Meghalaya, which too will be required to exchange enclaves with Bangladesh.

In 2014, a parliamentary standing committee on external affairs had tabled its report that was unanimously endorsed by the BJP, Congress and Trinamul. The BJP and Trinamul were initially against the swap.

The government's packed schedule in the week or so it has before the budget session concludes next month includes the passage of the goods and services tax (GST), black money and land acquisition bills.

While sources in the government sounded confident about the GST and black money bills, they were uncertain about the land bill.

Senior ministers plan to speak to AIADMK chief Jayalalithaa, who had opposed the GST regime on the ground that her state, Tamil Naidu, would lose out on revenues.

The Congress too had demanded in the Lok Sabha that the GST bill be referred to a parliamentary panel because of the changes the NDA government has brought in.

However, a late-evening statement from Rajya Sabha MP and spokesperson Rajiv Gowda hinted at a climb-down.

"The Congress," Gowda said, "has been a proponent of a common GST regime across India.... The decision of whether to refer the GST bill to a standing committee or a joint select committee will be taken by the party after detailed discussions within the Congress parliamentary party and taking into account the broad national consensus on the issue."