The indiscriminate application of synthetic colours has defaced and mutilated the original terracotta artistry of the temple, built in 1669 by Nadia king Raghab Roy, masking intricate carvings that had survived for more than three and a half centuries.

Regarded as one of Bengal's finest examples of terracotta architecture, the temple is a protected heritage monument under the West Bengal Preservation of Historical Monuments and Objects and Excavation of Archaeological Sites Act, 1957, figures in the state government's heritage register and is maintained by the state directorate of archaeology and museums.

The 1957 Act expressly prohibits the destruction, injury, alteration, mutilation, defacement, removal or decay of a protected monument and its adjoining land. Yet, the temple's exterior was allegedly painted in blatant violation of these provisions by a group of local people led by Manik Mukherjee, an unauthorised priest who earns by assisting devotees in offering prayers to a Shiva Linga at the site, although no official arrangement exists for such religious services.

Mukherjee admitted to getting the temple painted, claiming he acted in "public interest" because the structure was "decaying". He further claimed that local BJP MLA Sadhan Ghosh had facilitated official approval for the work from the subdivisional officer (SDO), Krishnanagar Sadar. However, Mukherjee failed to produce any document to substantiate the claim.

"Whatever I have done was as per official approval since the government took no care of the temple and the local MLA knows it," Mukherjee told The Telegraph.

MLA Ghosh, however, denied Mukherjee's claim. "I have no such authority. The priest came to me, but I told him I am not authorised to issue such permission," he said.

Nadia district magistrate Srikanth Palli did not respond to calls and text messages. Krishnanagar Sadar SDO Mouli Sanyal, who recently assumed office, said she was unaware of any approval for painting the protected monument.

Officials of the state directorate of archaeology in Calcutta said no painting, alteration or modification of the appearance of a protected monument was permissible, irrespective of the intention behind such work.

Heritage experts warned that the use of modern chemical paints had not only destroyed the temple's historical authenticity and aesthetic integrity but had also caused "irreversible damage" to its centuries-old terracotta surface, erasing an invaluable chapter of Bengal's architectural legacy.

Tapan Bhattacharya, former deputy superintending archaeological engineer of the Archaeological Survey of India, expressed shock over the incident.

"This is very shocking. The original character of the temple has been dangerously altered by the application of modern impermeable and glossy paints. The damage is irreversible and unacceptable," Bhattacharya said.

Explaining the scientific consequences, he added: "The performance of this ancient brick edifice depends on the natural movement of moisture through the pore structure of its old masonry. Water enters the structure through capillary action and escapes by evaporation through the pores of the bricks and traditional lime mortar. By coating the entire exterior with impermeable paint, moisture continues to enter the masonry but can no longer evaporate. The trapped moisture will eventually weaken the structure, accelerating dampness, deterioration and decay of this centuries-old brick monument."

Sanjit Dutta, a local historian in Nadia, termed the incident as "quite unfortunate". He blamed the administrative apathy in maintaining the heritage structure and a section of people with vested interests who are exploiting the situation.

"Awareness is needed at both ends; otherwise, days are not far away when iconic shrines and monuments that historically identify the Nadia district will not be available any more," Dutta told The Telegraph.