The Queen was kept in the dark for years by a palace traitor, MI5 documents reveal

Queen Elizabeth II was not officially informed for nearly a decade that one of her most senior courtiers had confessed to being a Soviet spy, according to recently released MI5 files.

Art historian Anthony Blunt was Surveyor of the Queen’s Pictures for decades, overseeing the official Royal Art Collection, and in 1964 he admitted that he had been a Soviet agent since the 1930s.

Documents released by MI5 show that although Blunt admitted to them that he had spied for the Russians during the Second World War, the late Queen herself was not officially told this for almost nine years.

When she was informed of the whole story in the 1970s, she was characteristically unflappable, taking it all “very calmly and without surprise,” according to declassified files handed over to the National Archives.

The decision to officially inform the Queen came amid growing concern in Whitehall that the truth would inevitably emerge after Blunt, who was seriously ill with cancer, died. Journalists were already investigating the story and were no longer constrained by concerns about defamation.

Suspicion first fell on Blunt in 1951, when fellow spies Guy Burgess and Donald Maclean fled to the Soviet Union.

He had been a close friend of Burgess since their time together in Cambridge in the 1930s – part of the so-called Cambridge Five spy group.

During the Second World War Blunt worked for MI5, after 1951 he was interviewed 11 times by the Security Service, but always denied espionage.

Then the American Michael Straight told the FBI that he was recruited as a Russian agent by Blunt himself.

In April 1964, MI5 investigator Arthur Martin confronted Blunt and promised him immunity from prosecution.

His full confession is included in these files for the first time. In addition to admitting his work during the war, he admitted to being in contact with Russian intelligence after the war.

Blunt said he met a Russian named Peter before Burgess and Maclean left, but he couldn’t remember exactly why. He said that the so-called Petar encouraged him to run away, but he refused.

The examiner said Blunt was “not at ease” as he spoke and each question “was followed by a long pause” as he “seemed to be debating with himself how to answer”.

Despite Blunt’s prominent position, few outside MI5 had heard of this confession. The Minister of the Interior and his highest civil servant were informed.

The Queen’s private secretary was told only that Blunt was involved and that MI5 intended to question him.

It was agreed that Blunt would be officially notified if she became seriously ill, as it might trigger press coverage of his past.

In March 1973, another note from the file records that the Queen’s private secretary spoke to her about the Blunt case. It reads: “She took it all very calmly and without surprise: she remembered that he had been under suspicion long after the Burgess/Maclean case was over”.

Miranda Carter, Blunt’s biographer, said her “hunch” was that Elizabeth II was informally told some time after 1965.

She believes officials “wanted to maintain a veil of plausible deniability.” That the monarch received the news “calmly and without surprise” suggests to Carter that she must have known.

Blunt’s past was finally exposed by Prime Minister Margaret Thatcher in a statement to the Commons in 1979. He died in 1983 aged 75 after being stripped of his knighthood.

• Cambridge spy Kim Philby has said he would do it all over again after finally admitting he was a Russian agent for years

• Blunt feared that his KGB chief would turn violent when he refused to join fellow spies Burgess and Maclean and flee to Russia

• Film star Dirk Bogarde was warned by MI5 that he could be the target of a KGB entrapment attempt

• MI5’s chief investigator was puzzled by Philby, admitting he could not establish whether he was a Soviet spy

Unlike government departments, MI5 is not subject to the Freedom of Information Act. He releases his archives as he chooses, and some files are partially redacted.

Some of the documents published today will be presented at an upcoming exhibition at the State Archives.

MI5 Director General Sir Ken McCallum said: “While much of our work must remain secret, this exhibition reflects our ongoing commitment to be open wherever we can.”