'You could tell by Christmas cards Diana sent that the writing was on the wall for her and Charles'
I was shocked at how Diana was treated after royal split, Paul Costelloe tells Bairbre Power
'Even then, you could tell by the Christmas cards we were getting how the relationship with Diana and Charles was slightly dividing. Once they were beside each other, then they were separated by the children, then they were separated by a fence and a field. You know how the camera can tell a story - the writing was on the wall."
Over a decade and more than a dozen commissions, designer Paul Costelloe got to know Princess Diana and they talked clothes, and children, over tea in her drawing room at Kensington Palace.
Twenty years after her death, the Limerick-born designer voices his shock at how Diana was treated after the couple's split.
"She wasn't looked after when they broke up. I mean, when you see those press images on television of when she was walking through airports and being totally pursued, practically mugged by photographers, that the palace didn't step in and give her a lot more security and control. I think that was totally shocking for anyone of that stature to be treated in such a demeaning way," he said.
Paul watched the Channel 4 documentary 'Diana: In Her Own Words', with its controversial footage recorded by her voice coach, Peter Settelen, in 1992/93, but does he think the princess would have welcomed the tape's contents being revealed now, 25 years later?
"She probably would have liked it, but I'm not sure that her sons liked it. It is sort of an embarrassment to the rest of the royal family that it's been brought out again as history," he said.
"I think the way Diana held herself, even at the worst times of her life, she's seemed to have had the courage to meet the public, show her face and go forward.
"I think there's a lesson to be learnt there. In times of crisis, don't hide away."
Paul believes the public are intrigued with the memory of Diana "because of what has come out from the report of her interview with her voice coach, and the whole background situation, which was very much hidden during her funeral and that short period afterwards when, in fact, it was Tony Blair who had to come in and smooth out some situation with the royal family. They just couldn't cope. They were on their knees.
"Certainly the royal family have come back to prove that she was a great mother by bringing up two incredibly well-behaved sons who know how to perform their royal duties and yet are very human to the ordinary person on the street. And that's what she was loved for.
"I think particularly Harry portrays her character very much, and carried her mantle forward. William is a little bit more conservative - obviously there is a little bit more of Charles in him. Certainly Harry seems to be the bearer of Diana's style and attitude."
Paul described Kensington Palace as a very quiet, "very subdued place and then Costelloe comes thundering in, falling up the stairs with my big enormous feet, and presenting Diana with a bunch of flowers".
"They obviously meant quite a bit to her and she always mentioned them afterwards," he said. "I'm glad I had that trait from my heritage and my family. It's better to give than to take and certainly in that situation, it was such a great pleasure for me."
Paul's son Gavin, now a barrister in London, was brought along as a youngster and Diana was "thrilled and delighted that I had brought him".
"He was there in the drawing room playing behind the couch with some toys while I was doing the fittings," he said.
Referring to the Channel 4 documentary in which Diana revealed how she was "traumatised" when Prince Charles was asked in their engagement interview if he was in love and famously replied 'whatever love means', Paul said: "That was a terrible statement. That was obviously the moment of truth."
That was 1981 and exactly a decade later, Diana stepped out in Ontario in her Paul Costelloe pink tailored suit with gold buttons, commissioned for the couple's visit to Canada.
The world's media was trailing their every move as rumours escalated about the state of their marriage. It was their last royal tour.
A year later, two weeks before Christmas, Buckingham Palace announced that Diana and Charles were separating.
The fairytale was over.