Canadian spies are set to help India's intelligence agencies to intercept BlackBerry messages to prevent the mobile e-mail service being shut down across the sub-continent.

The Indian Government believes that messages sent via the BlackBerry system, which is licensed to mobile operators by Research in Motion (RIM), a Canadian company, pose a threat to security because of the difficulty of tracing and intercepting them.

It has given the four domestic mobile operators that offer the service in India - Vodafone, Bharti Airtel, BPL Mobile and Reliance Communications - until the end of the month to detail how they route their users' e-mails. The demand comes after a refusal by the Ministry of Home Affairs to grant further BlackBerry licences. It acted after India's security services had raised doubts over whether they could “lawfully access” BlackBerry's encrypted system, which traffics messages between a handful of secure servers, all based outside India.

The move again places the security credentials of the gadget cherished by millions of corporate high-fliers in the spotlight. Assessments of the system vary: it is trusted by the British Government to relay “restricted” information. Others blacklist it as unsafe.

RIM insists that its technology is impregnable to spies. After France barred MPs and their advisers from using the system last year, RIM said that “rumours speculating that can be intercepted and read by the National Security Agency in the US or other 'spy' organisations are based on false and misleading information”.

Last week, RIM and its operator partners met officials from the Indian Ministry of Communications and Information Technology and representatives from the Canadian Embassy to try to prevent a BlackBerry blackout being imposed in India, sources said. It is understood that further contact between the two countries' security agencies was agreed in an effort to allay India's concerns.

RIM said that it would not comment on “confidential regulatory matters”. An estimated 400,000 of RIM's 12 million users are in India, a figure that is likely to rise rapidly.

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