Prince Philip's letters to Princess Diana that made her 'boil with anger'

Princess Diana and Prince Charles endured a bitter divorce that reverberated throughout the Royal Family.

Intimate details of their tumultuous marriage have emerged throughout the years, including during the inquest into Diana's death.

The 'People's Princess' tragically died aged 36 alongside boyfriend Dodi Fayed, 42, in a car crash in Paris in 1997.

And it's claimed Philip once sent letters to Diana, which made her 'boil with anger' and left her 'red-faced with fury'.

The notes saw Philip, now 98, criticise Diana's behaviour towards Charles during their bitter break-up.

The missives, sent in 1994 and 1995, came to light at Diana's inquest in 2008, when her confidante Simone Simmons spoke about them.

Ms Simmons, a spiritual healer, told the hearing she spoke to Diana for hours at a time over the phone - and recalled one conversation when the princess was 'furious'.

She told the inquest: "Diana read one out to me because she was absolutely furious and she was actually imitating the voice of the Duke of Edinburgh."

The pal added that Diana was going through her letters as she was reading a book about the study of handwriting.

Ms Simmons said one of the letters was handwritten, while the other was typed.

She claimed the princess let her see one of them after reading the other out loud.

The jury was shown redacted versions of other letters between the pair.

When asked if the Duke had made 'cruel and disparaging observations' about the princess's conduct, Ms Simmons replied 'yes'.

She agreed the letters had been 'extremely derogatory', with one of them leaving Diana 'red in the face'.