All of Corinne's 873 Facebook friends, and tens of thousands of their friends globally, can see her gun-toting picture on the networking site.
The picture on Corinne Sawers' Facebook page. (SOURCE: Facebook, The Mirror)
"It's a very silly thing for her to do," a former security source told the newspaper.
"Given the sensitivity of her dad's job, she should think twice about what she posts."
It's not the first time Sir John has been left red-faced over photos posted on Facebook.
His wife, Lady Sawers, put up a picture of Sir John wearing skimpy swimming shorts on her Facebook page last May when he was appointed the MI6 top job.
- AAP