The demolition was being carried out using excavators amid heavy security, with police and central forces deployed around the site, he said.
The Fire and Emergency Services personnel were also present as a precautionary measure.
The demolition triggered celebrations among BJP workers and supporters gathered in the area, who raised slogans in support of their party.
Abhishek is the TMC Lok Sabha MP from Diamond Harbour constituency, and Amtala is part of the constituency.
BJP MLA from Amtala Agnishwar Naskar alleged that the Abhishek Banerjee’s party office had been constructed in violation of building rules and welcomed the district administration’s action.
“The structure was built illegally, and the administration has finally acted in accordance with the law,” Naskar said.The action followed complaints alleging that the office had been constructed violating all regulations, the official said, adding that notices had been issued on July 15 to the persons concerned, asking them to appear for hearing as part of the statutory process initiated on the basis of the complaints.
“The administration has initiated proceedings strictly in accordance with the provisions of the law. Notices have been served after receiving complaints regarding alleged unauthorised construction, and the matter is currently under adjudication. Any further action will be taken only after the hearing and in compliance with the relevant legal provisions,” a senior South 24 Parganas district administration official told PTI.
Additional security arrangements were put in place around the Amtala party office from Saturday morning, with guard rails erected around the premises and senior police and civil administration officials visiting the site.
“We have made all necessary arrangements to ensure that the proceedings are carried out peacefully and in accordance with law. The demolition work is being done strictly on the basis of the legal process and the outcome of the hearing,” the official told PTI.
According to the notices issued by the district administration, the land on which the party office stands was allegedly purchased in the name of a company, Leaps and Bounds. The notices also sought clarification on documents relating to the ownership of the land and other records connected with the construction, officials said.
Administration sources said the authorities decided to proceed further after receiving no response to two notices issued to the persons concerned.


