The 500,000 users of the popular BlackBerry mobile e-mail service in India could possibly be facing a blackout if the Union Ministry of Home Affairs has its way.

CNBC-TV18's Sandeep Gurumurthi reports that Tata Teleservices' application to offer BlackBerry Services in India has been rejected after the Department of Telecom (DoT) forwarded the request to the Union Ministry of Home Affairs (MHA).

Anil Sardana, Managing Director of TTSL, told reporters in New Delhi that they were told by the MHA that the BlackBerry service does not allow for "lawful interception" mandated for all Value Added Services (VAS).

Sources tell CNBC-TV18 that when Tata Tele asked DoT why other operators were being allowed, DoT fired off letters to existing BlackBerry providers seeking an explanation. Sources also say that two rounds of discussion have happened between these operators and the MHA.

According to sources, existing service providers will meet the Telecom Secretary again next week. This meeting could be very crucial and would give an indication as to which way things are headed. Existing service providers will reply to Home Ministry concerns in 4-6 weeks.

A spokesperson from Research in Motion (RIM), the company that offers the BlackBerry service said: "RIM supports its carrier partners in India and we will work together with them to seek further clarity."

However, that statement is quite ambiguous and here's why: In June last year the French government had advised its officials not to use BlackBerry services for precisely the opposite reasons--the fear was that since Blackberry provided a server-based service, sensitive data could be exposed to espionage. At that time, officals at RIM claimed that even they did not have access to the data on their servers, which was what made the Blackberry service secure and hence popular with businesses.

So, if the Ministry of Home Affairs insists on having its way, it's not clear how RIM will provide for lawful interception. And if RIM caves in, the Canadian company will have some answering to do to Indian businesses and Chief Information Security Officers (CISOs) and may end up losing the 'secure' badge that it so proudly wears now.