Buckingham Palace is considering legal action over the leaking of film footage apparently showing the Queen and her mother performing a Nazi salute.
The Palace has also begun an inquiry into how the 17-second film clip ended up in the hands of The Sun newspaper and if there was "any criminality" -involved.
It will call in police if it finds any evidence the footage was -stolen from the Royal Archives, housed at Windsor Castle, The Sunday Telegraph understands.
It is now thought that the footage of the then Princess Elizabeth, aged six, her sister Margaret and the future Queen Mother performing the Nazi salute was filmed by the Queen's father, the future King George VI.
"Access to the Royal Archives is rare and covered by confidentiality agreements," said a source.
One possibility is that the footage could have been inadvertently handed to film-makers for a tribute documentary, as part of batch of Royal home movies.
Stig Abell, The Sun's managing editor, said the footage was -obtained by the newspaper "in a legitimate fashion".
- The Sunday Telegraph