The income tax “survey” of the BBC’s offices in New Delhi and Mumbai continued through Wednesday, and the officials were still inside at midnight — over 36 hours after they had arrived at 11.30am on Tuesday.

A source told The Telegraph that the BBC had asked the staff to work from home on Wednesday. Many of them were allowed to leave the office only on Tuesday night by the tax officials.

“The whole exercise is nothing but an act of intimidation. After sealing the office, the IT officials stayed overnight on the premises and the survey is still continuing for the second day. Some of the staff members, mainly from the finance department, were asked to stay back last night,” the source said.

The “survey” comes weeks after the BBC came out with a documentary critical of Prime Minister Narendra Modi. While the film was released by the BBC only in the UK, the Centre invoked emergency powers to block it from social media platforms in India. The film, India: The Modi Question, examines Modi’s role during the 2002 Gujarat riots. The income tax department has not yet issued a statement on the reason for the “survey”. Unnamed government sources have said it is part of an investigation into issues related to international taxation.

Sources said tax officials had been making copies of electronic and paper-based financial data of the organisation and that some computer peripherals and mobile phones were cloned. The source who spoke to this newspaper said journalists’ computers were also searched. “They claimed that the survey is part of a financial probe but shockingly they searched the computers of journalists and editorial staff. They have been very aggressive,” the source said. A former CBI joint director raised a question on the survey being conducted by the tax department.

“Where is the need for a physical survey even if they claim alleged tax evasion? They should have taken legal remedies, which they do in such cases. The whole exercise smacks of high-handedness and vendetta,” he said.

The Opposition has condemned the action against the independent broadcaster and contrasted it with the Modi government’s refusal to order an investigation into the Adani group, whose shares have plummeted, wiping out investor wealth, after allegations of accounting fraud and stock manipulation. In an internal memo to employees, BBC World Service director Liliane Landor said the income tax department was conducting a survey of the organisation’s “tax status and affairs in India”, with which the BBC was cooperating fully.

“If you are asked to meet with the officers you should answer their questions honestly and directly. “Questions about the BBC’s structure, activities, organisation, and operations in India are within the remit of the investigation and should be answered,” Landor said in the note, seen by Reuters. “It goes without saying that you should not delete or conceal any information on any of your devices.” A spokesperson for the BBC did not immediately respond to a request for further comment.