14 (UPI) --Documents newly declassified by MI5, Britain's internal intelligence agency ... only told her about the infamous Cambridge Five member and art historian, Anthony Blunt, who was employed as the monarch's surveyor of official pictures, in 1973 ...

Anthony Blunt, who worked at Buckingham Palace as Surveyor of the Queen’s Pictures, was secretly a Soviet spy during WWII.

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

Anthony Blunt, a royal art historian, confessed in 1964 to spying for the Soviets, but the late queen was not officially told about his past until 1973. View on euronews

Queen Elizabeth II was not told officially for nearly a decade that one of her most senior courtiers had admitted he was a Soviet spy, newly declassified British files revealed Tuesday.

Confessions of double agents and tips for new spies have been released as part of a tranche of recently-declassified documents from MI5. The documents are part of a new exhibition on display at the National Archives this spring and include details about some of Britain's most notorious spies.

When the Queen was finally told the full story in the 1970s, she was characteristically unflappable - taking it "all very calmly and without surprise".

Newly declassified British documents show that Queen Elizabeth II wasn’t told details of her long-time art adviser's double life as a Soviet spy because palace officials didn’t want to add to her worries.

Queen Elizabeth II wasn’t told details of her long-time art adviser's double life as a Soviet spy because palace officials didn’t want to add to her worries, newly declassified documents reveal.

Sir Anthony Blunt, the royal family's picture surveyor and renowned art historian, finally admitted that he had been a Soviet agent since the 1930s