The brother of Diana, Princess of Wales, has said he still has nightmares about the “harrowing” experience of her funeral.

Earl Spencer also recalled how the 1997 event must have been a “million times worse” for the Princess’ two sons William and Harry.

William, now the Duke of Cambridge, was 15 and Harry 12 when their mother was killed in a car crash in Paris on August 31 1997. A huge outpouring of grief followed her death, which shocked the world.

Earl SpencerEarl Spencer gave an address during the funeral in 1997 (John Stillwell/PA)

Earl Spencer, speaking to BBC Radio 4’s Today programme, said: “The feeling, the sort of absolute crashing tidal wave of grief coming at you as you went down this sort of tunnel of deep emotion, it was really harrowing and I still have nightmares about it now.

“So there was the inner turmoil of thinking, ‘My God this is ghastly’ but then the point of thinking these two boys are doing this and it must be a million times worse for them. It was truly horrifying, actually.”

Earl Spencer said he saw the eulogy for his sister as a chance to “speak for somebody who had no longer got a voice”, adding: “All I was trying to do was, as a brother, speak for my sister who was no longer there.”

The funeral processionEarl Spencer said the funeral must have been a ‘million times worse’ for Princes William and Harry (PA)

Told he had said some “pretty pointed things” during the speech while standing opposite the Royal Family, Earl Spencer replied: “I don’t feel I said many pointed things, I believe that every word I said was true and it was important for me to be honest.

“I wasn’t looking to make any jabs at anyone actually, I was trying to celebrate Diana – and if by doing that it showed up particularly the press, I think, in a bad way, well, they had that coming.”

He added: “In her final years in particular, Diana was really brought low by elements of the paparazzi and the tabloids.

“I remember she told me about one man who promised to hound her until the day she died and he would urinate on her grave.

“So she was dealing with a very dark side of the media and even at her funeral I thought it was appropriate to touch on that.”