The Hindu Swayamsevak Sangh UK -- operating in the country since 1968 – is ideologically inspired by the Rashtriya Swayamsevak Sangh and Britain's charities watchdog opened a statutory probe after concerns were raised on its "extremist" views and "improper" working this week.
The charity came under scanner after the ITV Network in its documentary 'Charities Behaving Badly' showed the HSS teacher at a youth camp in Herefordshire making controversial remarks against other religions when responding to questions.
"We are disturbed at the footage we have seen - some of which is so serious it is clearly a matter for the police," said Michelle Russell, director of investigations, monitoring and enforcement at Charity Commission.
"Rightly, the public will be concerned about the footage and the implications for public trust and confidence in these charities, and the potential impact on the charity sector more generally. We can reassure the public that we take these issues seriously," she said.
The statutory inquiry will investigate comments made by the individual invited to speak at the charity event in the presence of the charity's beneficiaries and the management and oversight by the trustees of such events.
"These kinds of incidents illustrate why it is important for the regulator to have the right tools to do the job. There are currently loopholes in the existing regulatory framework which we are seeking to close by looking for increased powers in the draft Protection of Charities Bill," Russell said.
The commission said that in the case of HSS UK, this is new information that has been brought to its attention and that has resulted in immediate regulatory action.
UK-based Islamic and Sikh charities have also faced similar heat.
In the case of an Islamic charity, Global Aid Trust, the chief executive has stepped down after the ITV investigation staff was caught by praising terrorists and even offering advice on how to become a jihadist in Syria.
The trust is also the subject of an ongoing fraud investigation by the UK's National Terrorism Financial Investigation Unit.
The trustees of both Global Aid Trust Limited and HSS UK have been notified of the commission's decision to open the inquiries and both have complied with the commission's requests for information and documents to date, the commission said.
HSS UK stressed that the individual caught on camera was not an office-bearer, adding that it will take "even greater care that no views are expressed from its platform that could directly or indirectly promote interfaith discord".
The commission said it is awaiting access to all of the footage obtained relating to the charities so that this can be reviewed and the regulatory concerns addressed through the investigations that have been opened.
It will publish a report at the conclusion of each inquiry.
In a case unrelated with the TV probe, the commission has opened a statutory inquiry into Khalsa Missionary Society, which was set up to advance the Sikh religion in the UK through prayer meetings and lectures, and producing literature on Sikhism.
The inquiry has been opened as a result of an ongoing investigation by the Home Office into suspected immigration abuse.
The commission will examine if the charity was set up and registered for an improper purpose and if the trustees have misused charitable funds.