RCMP feared traitor Kim Philby knew 'most interesting' Canadian secrets: documents

British intelligence eventually learned of Philby’s treachery and confronted him in Beirut in late 1962. Early the next year, Philby slipped aboard a freighter to the Soviet Union, where he was granted asylum and lived until his death in 1988.

On July 1, 1963, the U.K. House of Commons was told of Philby’s spying for Moscow and his apparent disappearance “behind the Iron Curtain.”

Philby, Guy Burgess, Donald Maclean, Anthony Blunt and John Cairncross would become known as the Cambridge Five spy ring, named for the renowned British university they had all attended.

It was revealed in the U.K. Commons that more than a decade earlier, Philby had warned Maclean, through Burgess, that western security services were closing in on him. Burgess and Maclean defected to the Soviet Union in 1951.

During Philby’s time in Washington, he was also accredited to Ottawa and had contact with Canadian security officials. The 1963 confirmation of Philby’s subterfuge on the Soviet Union’s behalf prompted members of Canada’s foreign ministry and the RCMP to review their dealings with him.

On July 11, 1963, RCMP counter-intelligence official Jim Bennett received a call from the Canadian foreign ministry requesting a copy of any summary the Mounties were preparing on Philby.

Library and Archives Canada disclosed hundreds of pages of security records on the Philby case in response to an Access to Information request from The Canadian Press.

Although some of the documents are more than six decades old, many pages were heavily censored prior to release. CP has filed a complaint with the federal information commissioner in a bid to see more of the file.

A Sept. 10, 1963, memo from Bennett to another senior RCMP security official said that, since Philby likely was a Soviet agent during his time in Washington and had duties involving Ottawa, “it is essential that we examine the damage he may have caused to our security.”

Bennett wrote that it “must be assumed that he had virtually complete access to the most interesting and promising aspects of our counter-espionage and counter-subversive operations.”

He noted that RCMP security officials Len Higgitt and Charles Sweeny recalled four major operations that “were probably discussed with Philby.”

Among them were “investigative leads” flowing from the case of Igor Gouzenko, a Soviet cipher clerk in Ottawa who defected to Canada at great personal risk in September 1945 with a trove of valuable secrets.

Gouzenko’s revelation of a Soviet spy network operating in Canada is widely considered to be a key event in the dawn of the Cold War. 

It turns out RCMP security officials were right to be concerned about Philby’s knowledge of the Gouzenko case, as the British double agent’s role at MI-6 in the mid-1940s allowed him to limit the damage to Moscow.

Gouzenko’s documents led to the March 1946 arrest of British scientist Allan Nunn May for divulging atomic secrets, including isotope samples, to the Soviets.

It would later emerge, however, that Philby helped to delay the arrest by warning Moscow of an October 1945 plan to catch May in the act of meeting a Soviet intelligence contact near the British Museum in London.

Philby probably also advised Moscow “about other Soviet agents who were under British and American surveillance,” wrote Christopher Andrew in “The Defence of the Realm,” an authorized 2009 history of MI-5, Britain’s domestic security service.

“On at least one occasion, an agent identified by Gouzenko was able to escape from America, probably to the Soviet Union, despite being under active surveillance by the FBI,” the book says. A warning from Philby “may well have prompted the escape,” it adds.

Beyond Gouzenko, descriptions of three other major operations the RCMP likely discussed with Philby were stripped from the 1963 Bennett memo before its release under the access law.

In December 1967, the publication of articles in the Soviet press prompted Higgitt, who had become RCMP security and intelligence director, to send a memo to the foreign ministry saying “careful study over the past several years” led the Mounties to conclude that the damage “caused by Philby’s treachery was minimal.”

Higgitt was quick to add that he could not speak for other members of the Canadian security community, such as the Joint Intelligence Bureau or the Communications Branch of the National Research Council, a signals intelligence agency.

“Having regard to the state of the art in Ottawa at that time, however, it is probable that the situation would be fairly similar,” Higgitt wrote.

“Fortunately during the years in question, the activities of the Soviet Bloc intelligence were at a low ebb insofar as Canada was concerned.”

A federal government statement, drafted in 1968 in anticipation of publicity about Philby’s memoirs, also said any damage he might have caused to Canadian interests while in Washington “has been assessed as minimal.”

Intelligence expert Wesley Wark described the redactions to the Philby records as ridiculous, given the passage of time.

It would have been helpful to see the full RCMP damage assessment of Philby’s activities, if it survives, said Wark, a senior fellow at the Centre for International Governance Innovation.

“But at least we have the summary,” he said. “And the summary strikes me as probably pretty realistic.”

The RCMP’s conclusion that Philby didn’t do much damage — because Canada had few genuine secrets at the time — reflects the fact that Ottawa was in the early stages of bolstering its intelligence system following the Second World War, Wark said.

“It’s pretty accurate as far as it goes,” he said. “There wasn’t a whole lot that the Canadians were doing that was of super-sensitive nature.”

This report by The Canadian Press was first published Sept. 13, 2025.