Princess Diana took a fridge filled with her own blood when she went abroad in case she suffered any medical problems, including being attacked.
Her former private secretary Patrick Jephson explained that he and the rest of the security team also had their blood types checked to see if they were a match in case she ever needed it.
He claims the extreme measures were necessary as Diana was "quite often under threat".
And Diana wasn't the only one, as the Queen and Prince Charles also carry spare blood with them in case of an emergency.
Jephson said: “Particularly when we were abroad or in the developing world, we would carry a little refrigerator full of spare supplies of Diana’s blood", reports the Daily Star.
He continues: “That sure took the glamour out of it.
“Each of us were tested so the doctors knew which of us could give her blood if she needed it.
“Diana was quite often under the threat of physical danger.
“A part of the job that was easy to forget and then you’d get a sharp reminder.”
Patrick worked with Diana from 1988 until 1996, and saw first hand the upset caused by her split from Prince Charles.
He still hasn't forgiven the royals for how they treated her and believes the Queen and the rest of the family underestimated Diana.
He said: "That is a real shame, and I think it doesn’t really reflect well on the royal family.
"She was out there flying the flag for Britain and by any measure doing a great job for the monarchy, but received very little recognition let alone thanks for it at the time.
"She was a young single mother working hard and she had no supportive network, she had no proper mentoring, the organisation was overwhelmingly masculine even though there was a woman at the top of it.
"She really had her work cut up just surviving, let alone driving as a royal performer.
"I think they did underestimate her.
"It’s a real shame they didn’t realise what an asset they had.
"Princess Diana was not a natural rebel, she was a natural monarchist.
"She should have been their greatest asset, but they let that slip through their fingers."
