Two decades after British Broadcasting Corporation (BBC) journalist Martin Bashir’s explosive interview with Princess Diana for an investigative documentary series Panorama in 1995, an independent inquiry has said that BBC fell short of "high standards of integrity and transparency" and Martin Bashir used “deceitful behaviour” to secure the interview with Princess Diana.

The BBC appointed a retired senior judge in November last year to investigate Diana’s brother Charles Spencer made renewed complaints that Bashir used false documents and other dishonest tactics to persuade Diana to agree to the interview.

Spencer had alleged that Bashir showed him fake bank documents relating to his sister's former private secretary and another former royal household member, intending to gain access to Princess Diana.

The findings of the inquiry were published on Thursday and the BBC and Bashir have both apologised. The BBC has written apologies to Prince Charles and Earl Spence as well as Princes William and Harry.

What’s the interview in question?

BBC journalist Martin Bashir conducted an interview with Princess Diana for BBC’s Panorama programme which was aired on November 20, 1995. It was a huge scoop for BBC because never before had any serving royal has spoken in such candid terms about life in the royal family.

In the 55-minute interview, Princess Diana talked about various subjects and poured her heart out about the disappointments with her marriage. This is the same interview where she had famously said that “there were three of us in the marriage, so it was a bit crowded,” with regard to Charles’ affair with Camilla Parker Bowles, to which he had admitted publicly the previous year.

She also admitted to having been unfaithful to Prince Charles in a five-year-long affair with cavalry officer James Hewitt. Diana also spoke about having suffered from postnatal depression after the birth of Prince William, and that she even tried injuring herself during the period.

She spoke at length about the impact that excessive media interest in everything she did had on her mental health and marriage, and how she was never given credit for anything good she did.

More than 20 million people watched the interview and sent shockwaves through the country and the monarchy. The British media described the interview of Princess Diana to the BBC as one that “plunged the monarchy into the greatest crisis since the abdication”, referring to King Edward VIII abandoning his throne in 1936 to marry an American divorcee.

At the time the interview was aired, the couple had already been living separately for three years. However, shortly afterwards, the Queen wrote to Prince Charles and Princess Diana telling them to divorce. A year later in 1996, Princess Diana divorced Prince Charles

Who is Martin Bashir?

Martin Henry Bashir is a British journalist and news anchor. He shot to fame with his sensational BBC interview with Princess Diana that detailed her collapsing marriage to Prince Charles.

Apart from the Diana interview, he had also done a similar bombshell documentary on Michael Jackson in 2003 which catapulted him to high-profile jobs in the United States, including as anchor on ABC's "Nightline" and as a political commentator for MSNBC.

He was suspended from MSNBC in 2013 after he made on-air comments he later described as "unacceptable" about former vice presidential candidate Sarah Palin.

He returned to the UK in 2016 and was reemployed by the BBC. He worked at the BBC as a religion editor. He resigned from his post in May this year because of ill health.

What did the investigation say about the BBC and Martin Bashir?

Lord Dyson, the retired judge who led the inquiry, said that Martin Bashir breached BBC rules by mocking up fake bank statements to gain access to Princess Diana and showed the fake documents to Princess Diana's brother Charles Spencer to gain his trust.

The report says Bashir "lied and maintained the lie until he realised that it was no longer sustainable. This was most reprehensible behaviour which casts considerable doubt on his credibility generally".

The Dyson-led investigation also came down heavily on BBC and criticised its conduct in the matter. The report found that BBC tried to cover up when it had learnt about how Bashir secured the interview. The Dyson report also criticized BBC internal inquiry in the matter in 1996, in which it had cleared Bashir, Panorama and BBC News of any wrongdoing. The report that the previous inquiry was inadequate because it failed to interview Charles Spencer.

It also criticised the BBC for giving evasive responses to press inquiries and said that BBC “fell short of the high standards of integrity and transparency which are its hallmark".

The BBC has accepted the finding of the inquiry and offered an unconditional apology to the royal family. The broadcaster also said it was handing back the awards the programme won for the interview.

How did the royal family react?

On Thursday, Prince William issued a statement, hitting out at the BBC and Martin Bashir over the “the deceitful way” to obtain an interview and for contributing to his mother Princess Diana’s "fear, paranoia and isolation".

"It brings indescribable sadness to know that the BBC’s failures contributed significantly to (Diana's) fear, paranoia and isolation that I remember from those final years with her," Prince William said in the statement issued from Kensington Palace.

"It is my view that the deceitful way the interview was obtained substantially influenced what my mother said. The interview was a major contribution to making my parents’ relationship worse and has since hurt countless others," he added.

Prince Harry echoed his brother’s words and blamed "a culture of exploitation and unethical practices" for their mother's death in a car wreck in Paris when she was being pursued by paparazzi.

"Our mother was an incredible woman who dedicated her life to service," Harry's statement read. "She was resilient, brave, and unquestionably honest. The ripple effect of a culture of exploitation and unethical practices ultimately took her life. To those who have taken some form of accountability, thank you for owning it. That is the first step towards justice and truth," he said.

Princess Diana was married to the Prince of Wales, Prince Charles, the heir to the throne, in London's St Paul's Cathedral, in 1981. But the couple separated in 1992 and divorced in 1996. She died in 1997 at age of 36, after the car she was in crashed in the Pont de l'Alma tunnel, in Paris.