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 ...

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.

Queen Elizabeth II was not officially informed for nearly a decade that Anthony Blunt was a Soviet spy, newly declassified documents reveal.

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. The files about royal art historian Anthony Blunt are among a trove from the intelligence agency MI5 released on Tuesday (Wednesday AEDT) by Britain's National Archives.

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

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

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.

Members of the spy ring in the 1930s spilled secrets to the Soviet Union from the heart of the U.K. intelligence establishment.