A policeman guarding Duchess Catherine while she travelled to the Caribbean left "secret" documents on a plane.
The file was found on the British Airways Boeing 777 jet which the Duchess of Cambridge and her six-month-old son Prince George boarded on their way to St Lucia before they caught a private plane to Mustique, according to The Sun newspaper.
Police have reportedly confirmed the mistake but insist the file did not contain any classified information.
This was the Duchess of Cambridge’s – known as Kate Middleton before she wed Prince William – first holiday with George and she joined her family who were celebrating mother Carole Middleton’s 59th birthday.
The brunette beauty was spotted leaving the plane carrying the tiny tot and although there were a number of people around them they managed to "escape their attention".
A source previously said: "Kate left the plane carrying her son like any other proud new mother. Everyone in her party had huge smiles on their faces as they walked across the tarmac to take a second, smaller plane, which took them on to Mustique.
"There were lots of other tourists surrounding them, but the Duchess and her little boy escaped their attention."
William was missing from the trip, having stayed behind in the UK to complete a 10-week-long agricultural course at Cambridge University.
Duchess Catherine’s guard leaves files on plane
