Prince William has welcomed the BBC’s decision to appoint a former supreme court judge to investigate how Martin Bashir obtained an interview with Princess Diana in 1995. Lord Dyson has been asked to investigate whether the BBC swept Bashir’s use of fake bank documents under the carpet when its original internal investigation cleared the award-winning journalist of wrongdoing. The Duke of Cambridge tentatively welcomed the investigation into the BBC interview with his mother, saying: “The independent investigation is a step in the right direction. It should help establish the truth behind the actions that led to the Panorama interview and subsequent decisions taken by those in the BBC at the time.” Interest in the largely forgotten topic has been revived in recent weeks following a series of programmes by Channel 4 and ITV marking the 25th anniversary of the original Panorama interview, in which Diana discussed her relationship with Prince Charles and declared “there were three of us in the marriage”. Many details of how Bashir obtained the landmark interview had already been made public following leaks to the media in 1996, including his use of mocked-up financial records to win the trust of Diana’s brother. However, BBC documents obtained this year following freedom of information requests by Channel 4 and ITV documentary teams have shed light on the original internal investigation that cleared Bashir of wrongdoing. This internal inquiry, led by Tony Hall, who went on to become BBC director general, concluded that Bashir was a fundamentally honest individual who “wasn’t thinking” when he asked for the bank statements to be mocked up. Hall told the BBC’s top executives that the graphic designer who carried out Bashir’s orders would never work for the BBC again. Hall also said the BBC had received a handwritten note from Diana herself in which she made clear the fake documents were not the reason she had chosen to do the interview. The BBC repeatedly said in response to freedom of information requests that it had lost the note. However, on Friday the corporation announced that the note had been recovered and would be submitted to the independent inquiry. Bashir went on to have a stellar career at ITV and US television news stations, having made his reputation with the Diana interview. He rejoined the BBC in 2016 and is currently its religion editor, although he has yet to answer questions on the Diana interview as he is signed off sick. Dyson, who was the second most senior judge in England and Wales, will conduct a full examination of how the BBC obtained the interview, whether the tactics fitted with the BBC’s standards at the time, and the extent to which Bashir’s tactics influenced Diana’s decision to give an interview.