Left to right: ACN Nambiar, an unidentified lady, Netaji Subhas Chandra Bose, Amiya Nath Bose and Emily Schenkl in Badgastein, Austria. Left to right: ACN Nambiar, an unidentified lady, Netaji Subhas Chandra Bose, Amiya Nath Bose and Emily Schenkl in Badgastein, Austria.

As more damaging revelations tumble out of the snooping on Netaji Subhas Chandra Bose's family by the Jawaharlal Nehru government, a declassified document from National Archives shows the Intelligence Bureau (IB) informed British internal secret service MI5 about its discoveries.

A senior IB official wrote on October 6, 1947, to his MI5 counterpart in New Delhi, attaching a copy of a letter intercepted from key Netaji aide A.C.N. Nambiar in Switzerland to Netaji's nephew Amiya Nath Bose in Calcutta. "Which masters was the IB serving when it was informing a foreign intelligence service about freedom fighters?" asks Anuj Dhar, author of 'India's Biggest Cover-Up' on the Netaji mystery. The IB's recently declassified papers, now placed in National Archives and accessed by Mail Today and India Today, show the Nehru government snooped on the Bose family between 1948 and 1968. This single-page document precedes the declassified documents by at least one year.

Balakrishna Shetty, then IB's deputy director, wrote to K.M. Bourne, a 'Security Liaison Officer' posted in New Delhi. Shetty, who worked directly under the first IB chief Sanjeevi Pillai and his successor B.N. Mullick, wrote that Nambiar's letter was "seen during secret censorship" (a euphemism for snooping).

Nambiar, who went to Berlin as a journalist in 1924, worked with Netaji and later with Nehru. His letters to the Bose family continued to be intercepted while he was posted as an Indian diplomat in Switzerland. Documents declassified by National Archives in 2014 show that MI5 believed Nambiar to be a Soviet spy.

"We would be grateful for your comments on this letter," Shetty asked Bourne on Nambiar's letter to Netaji's nephew.

The real-life Bourne preceded Robert Ludlum's fictitious spy Jason Bourne by several decades. K.M. Bourne was a former wartime military intelligence officer, later posted to India. A supplement to the London Gazette notification of June 20, 1947, mentions Major Bourne of the British Army's Intelligence Corps relinquishing his commission on September 26, 1946, and getting the honorary rank of Lt Colonel.

V. Balachandran, a former special secretary of RAW, termed the Bourne document "very, very significant". He said: "This confirms revelations in the Christopher Andrew's The Defence of the Realm, The Authorised History of MI5 in 2009 that Prime Minister Nehru allowed an MI5 agent, called a 'Security Liaison Officer', in New Delhi."

Hart was the director of counterespionage in MI5 during the Second World War and his job involved hunting out enemy spies posted in British dominions. Andrew reveals how Liddell, as deputy director, was able to persuade the Indian government to keep MI5's liaison officer in New Delhi even after Independence.

"What was not made public, however, was that during a visit to India in March 1947, the DDG, Guy Liddell, obtained the Nehru government's agreement for an MI5 officer to be stationed in New Delhi, after the end of British rule... In all other newly independent Commonwealth countries, as in India, the continued presence of an SLO became a significant, though usually undisclosed, part of the transfer of power," Balachandran said.

The document is the missing piece in a puzzle and confirms how surveillance on the Bose family started by the British intelligence agencies continued well after Independence. Saying that the post of MI5 liaison officer continued at least until the 1970s, Balachandran believes the British intelligence agency managed to influence the IB about focusing on communism as a major threat to internal security.