Chief minister Mamata Banerjee on Sunday asked Prime Minister Narendra Modi to immediately withdraw a Union home ministry notification that extends the jurisdiction of the Border Security Force (BSF) from 15km to 50km within Indian territory from the international borders Bengal shares with neighbouring Bangladesh, Nepal and Bhutan.

The wider footprint will bring around 37 per cent of the total geographical territory of Bengal within the ambit of the central paramilitary force, Mamata has pointed out in a letter to Modi.

The entire territory of Bengal adds up to “88,752sqkm, of which around 32,400sqkm (equivalent to 37 per cent of the state’s total territory) will come within the expanded territorial jurisdiction of the BSF, and thus interfere with the executive powers of the state and the state police’s ability to maintain the law and order in such areas”, the letter said.

On October 11, the Union home ministry came up with a notification that empowers the BSF to conduct raids and make arrests and seizures in areas located within 50km from the borders without requiring permission from the state police.

Mamata, who usually does not make political statements during the festive season, broke her silence on the issue on Sunday. “It is just an attempt to try and grab control over a considerable area of the state,” she said in Siliguri.

A retired police officer agreed: “What the chief minister has mentioned is absolutely correct. If we consider the entire north Bengal region and Murshidabad district, an estimate indicates that the BSF will have access to the entire area spread across as many as 70 police stations. The number is likely to touch 100 if we consider other districts like Nadia and North 24-Parganas which also share borders with Bangladesh.”

After the notification was issued, several trade bodies in Bengal and exporters had expressed fear that the smooth flow of goods could be affected and local economies in the border districts harmed.

Opposition parties such as the CPM and the Congress, too, had raised questions.

Charanjit Singh Channi, chief minister of Punjab that shares borders with Pakistan, too had voiced objections.

In her letter, Mamata has mentioned that altogether, the BSF would have jurisdiction in 11 districts of the state while underscoring some of the practical problems that would crop up.

“Most of the areas which will now fall under the newly delineated jurisdiction of the BSF are densely populated, and extending the powers of the BSF in such areas is fraught with the potential issues which are bound to arise when a force unfamiliar with the local populace, language, geography and society, is also put in the charge of administering law and order in such areas,” the chief minister said.

In the three-page letter, she has elaborated on the police infrastructure of Bengal which has three zones, 10 ranges, 29 police districts, seven commissionerates, 631 police stations with 491 outposts and other specialised units.

The state police are “thus well-equipped and better-placed than the BSF to promptly respond to any situation in the areas affected by the notification”, Mamata has written to Modi.

Mamata, who has time and again protested the Centre’s attempts at usurping the state’s powers, has accused the Modi government of creating a parallel investigating agency for offences that fall within the state police’s jurisdiction.

“In a federal structure, the requirement of obtaining the relevant state’s concurrence and consent is central to the exercise of jurisdiction of any central force, such as the BSF, in the state. Given the absence of such concurrence, the notification is a violation of the basic structure of the Constitution, of which federalism is an inviolable part,” the chief minister said in the letter.

Mamata, who reached Siliguri on Sunday afternoon on a five-day visit, said at a public event: “Some people… have taken such a decision politically…. We don’t endorse it. We have good relations with Bangladesh, Bhutan and Nepal and don’t need such extension of jurisdiction here. It is just an attempt to try and grab control over a considerable area of the state.”

Trinamul sources said the letter — and the brief comment at the Siliguri event — were the beginning of a long-drawn protest the chief minister was planning on the issue.