The politician – who is also a journalist – has issued a statement welcoming Lord Dyson’s report into the circumstances surrounding the interview, but he also said it has been “a long time coming”.
The inquiry found that the corporation covered up "deceitful behaviour" used by Mr Bashir to secure the explosive interview, with the findings prompting condemnation from Prince William and Prince Harry.
Mr Nicolson said the BBC is “right to apologise for its actions and to return the awards” it won for the programme. “However, the corporation has many questions to answer,” he continued. “Specifically, why did the then-head of news, Tony Hall, describe Martin Bashir as honourable when he knew he’d lied over the process used to secure the Princess Diana interview?”
Lord Hall, who led a botched internal investigation into the interview in 1996, is facing questions over why Mr Bashir was rehired by the BBC in 2016 – and these have been echoed by Mr Nicolson.
Lord Hall has now quit as chairman of the National Gallery, saying: “I have always had a strong sense of public service and it is clear my continuing in the role would be a distraction to an institution I care deeply about... I am very sorry for the events of 25 years ago and I believe leadership means taking responsibility.”
Mr Nicolson has also criticised the “unforgivably cruel” treatment of whistleblower Matt Wiessler – a graphic designer who was asked by Mr Bashir to create forged bank statements to help obtain the interview.
“Regaining trust will now need to be a top priority for the BBC,” the Scottish politician said, adding that neither current director-general Tim Davie nor chairman Richard Sharp come from a journalistic background. He called for the BBC board to be strengthened with members who do have such experience. “The cover-up culture at the BBC is longstanding and must now be addressed.”