The paparazzi photographers who "harassed" Diana, Princess of Wales during her life have been condemned by her sons in a new documentary.
William said a "pack" would hound and chase his mother, spitting at the royal and calling her names to get a reaction.
Prince Harry alleged those that pursued her car on the night she was killed in a Paris car crash took pictures of his mother as she lay dying on the back seat.
Speaking in the BBC documentary Diana, 7 Days, William said today people would find the treatment of his mother "utterly appalling".
He added: "We'd go looking for her to talk to, play, to do whatever, she'd be crying. And when that was the case it was to do with press.
"She'd had a confrontation with photographers on the way to the gym, on the way outside, just trying to do day-to-day stuff.
"The damage for me was being a little boy aged eight, nine, 10, whatever it was, wanting to protect your mother and finding it very difficult seeing her very upset.
"About every single time she went out there'd be a pack of people waiting for her.
"And I mean a pack - like a pack of dogs - followed her, chased her, harassed her, called her names, spat at her, tried to get a reaction to get that photograph of her lashing out, get her upset."
His brother said on one occasion she stopped the car on the way to the gym with the royal brothers on the back seat and confronted those pursuing her before returning, crying.
The 36-year-old princess and her boyfriend Dodi Fayed, 42, were killed along with chauffeur Henri Paul when their Mercedes crashed in the Pont de l'Alma tunnel in Paris on August 31 1997.
They were being pursued by paparazzi after leaving the Ritz Hotel for Mr Fayed's apartment.
In 2008 after hearing evidence over six months, an inquest jury returned a verdict of unlawful killing, saying driver Henri Paul and the paparazzi shared the blame for the deaths of Diana and Mr Fayed.
Speaking in the documentary which will be screened on Sunday, Harry added: "One of the hardest things to come to terms with is the people who chased her into the tunnel were the same people who were taking photographs of her while she was still dying on the back seat of the car.
"And William and I know that, we've been told that numerous times by people that know that was the case.
"She'd had quite a severe head injury but she was very much alive on the back seat. And those people that caused the accident instead of helping were taking photographs of her dying on the back seat.
"And then those photographs made their way back to newsdesks in this country."