Thirty years after the broadcast of the most infamous interview in BBC history, a new book looks at what led to Martin Bashir's deception of Diana, Princess of Wales and how the BBC reacted afterwards.

Dianarama, written by Andy Webb, re-examines the Panorama interview in which the late princess famously said there were "three of us" in her marriage with Prince Charles, now the King.

Former Panorama reporter Bashir secured the interview with Diana in 1995 after showing her brother faked bank statements that suggested people close to the princess were being paid by the security service MI5.

The book says Earl Spencer, Diana's brother, did not at first criticise Bashir over the interview because he did not want to say anything that would question Diana's decision to speak to him.

"To come out as a strong critic of Bashir would have been in effect to paint his sister as a gullible fool," writes Webb. "Far better to say nothing than to open a family rift."