Exposed: The BBC’s failure to properly investigate Martin Bashir’s Diana interview

It was only 38 words long but, written in her distinctive handwriting, the note from Diana, Princess of Wales, convinced BBC bosses that they had nothing to worry about and was key in their decision to brush the looming scandal under the carpet.

Within weeks of Panorama airing the bombshell Diana interview in 1995, concern began to grow in the upper echelons of the corporation that Martin Bashir, the junior reporter who had landed the scoop, may have hoodwinked the Princess into taking part.

Despite initially accepting his assurances that he had not shown copies of mocked-up bank statements to Diana, they asked him to provide some independent evidence.

Within hours, Bashir had returned brandishing the golden ticket – a note which, as far as they were concerned, put the matter to bed.

It read: "Martin Bashir did not show me any documents, nor give me any information that I was not previously aware of. I consented to the interview on Panorama without any undue pressure and have no regrets concerning the matter."

The note was written on Kensington Palace notepaper, and bore Diana's signature. It was revealed in full for the first time in Lord Dyson's damning report.

In his findings Lord Dyson highlighted the importance that the BBC attached to the letter. He stated: "BBC management believed that this note put an end to any concerns about the methods deployed, in particular by Mr Bashir, in securing the interview."

In order to verify that the note was genuine, Lord Dyson approached Harbottle & Lewis, solicitors to Princes William and Harry, who confirmed it was not a forgery.

However, while it certainly confirmed that Diana had no problem with the way the bombshell interview had turned out, it did not get Bashir or the BBC off the hook.

As Lord Dyson's report found, there were many urgent questions that remained about Bashir's conduct in the lead up to the interview.

The fake bank statements, which Bashir had persuaded unwitting graphic artist, Matt Wiessler, to produce, purported to show that people close to Diana and her brother Earl Spencer were in the pay of the tabloid press and the security services.

It was these documents that Bashir used to persuade the Earl to introduce him to his sister.

Mr Weissler, realising the part he may have played in the duplicity, reported his concerns to the BBC, which then began an investigation involving executives Tim Gardam and Tim Suter, and Steve Hewlett, Panorama's editor.

They called Bashir in to explain himself, but were quickly reassured when he lied and said he had not shown the fake documents to anyone.

When he presented them with the Diana letter, they were satisfied the matter would go no further.

Mr Gardam told Lord Dyson it never occurred to them at the time that Bashir was lying or that he might have shown the documents to Earl Spencer.

In his report, Lord Dyson was scathing about this approach from senior BBC executives for failing to consider that Bashir might have shown the documents to the Earl.

However, Lord Dyson added: 'I do not consider that it would be reasonable to criticise Mr Gardam for failing to ask Earl Spencer for his version of the facts.'

Despite the comfort felt at the BBC, the scandal was showing no signs of going away, with several journalists now circling around the story. In March 1996, a Sunday newspaper approached Earl Spencer, who in turn contacted the BBC to raise his own concerns about Bashir's conduct.

For a second time, BBC managers called Bashir in – and for a second time he lied, insisting he had not shown the fake documents to Diana or Earl Spencer. Later that day, however, under further questioning from Mr Gardam,he admitted that he had in fact shown the documents to Earl Spencer.

In his report, Lord Dyson said: "There is no doubt that Mr Bashir had 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.

"But it was not as reprehensible as commissioning the fake statements in the first place and using them in the way that I have described to induce Earl Spencer to introduce him to Princess Diana."

The BBC now had a problem in how it dealt with Bashir and how it explained its own conduct in the mounting scandal.

Tony Hall, the head of news and current affairs at the time, demanded that a further investigation was held to get to the bottom of the matter.

Bashir was questioned at length and following the interview, Mr Suter drafted a letter which read: “I have consulted Tony Hall and others within the senior management of News and Current Affairs, and it is clear to us, from the account you have given and from the corroboration we have received, that your dealings with the Princess in securing the interview were absolutely straight and fair.

"We are completely satisfied that the interview was freely given; that the Princess was placed under no pressure by you or anybody else; and that she was neither shown any documents nor told anything she did not already know."

The letter reprimanded Bashir for mocking up the documents, but Lord Dyson said it was probable that it was never actually sent.

Lord Dyson concluded: "I do not consider that Lord Hall and Mr Suter were justified in concluding, even on an interim basis, that Mr Bashir’s dealings with Princess Diana in securing the interview were absolutely straight and fair."

Anne Sloman, who had replaced Mr Gardam in March 1996, joined Lord Hall to conduct the urgent investigation.

They held a lengthy summit meeting with Bashir at which he was said to be "remorseful and tearful".

Lord Dyson stated: "The importance to the BBC of the meeting of 17 April 1996 is demonstrated by the fact that Lord Hall participated in it. It was unusual for someone in Lord Hall’s senior position to participate in a meeting with a relatively junior reporter."

But they still failed to see Earl Spencer's version of events.

Misleading press briefings were issued by the BBC which Lord Dyson said had fallen below the standards of fairness and integrity expected from the corporation.

Following the meeting, Ms Sloman wrote a note that read: "The Diana story is probably now dead unless Spencer talks. There is no indication that he will."

Lord Dyson said the BBC’s failure to approach Earl Spencer over the issue was one of the major failings. He concluded: "In my view, the failure to interview Earl Spencer was a most serious flaw in the investigation. Without hearing from him, Lord Hall and Mrs Sloman were at a grave disadvantage.

"They were denied the benefit which has been accorded to me to assess Mr Bashir’s evidence in the light of that of Earl Spencer."

Lord Dyson said, having had the advantage of speaking to both Bashir and Earl Spencer, "I have had no difficulty in preferring the evidence of Earl Spencer".

He continued: "If Lord Hall and Mrs Sloman had questioned Earl Spencer, they would have been able to test Mr Bashir by asking him to comment on Earl Spencer’s detailed account. In my view, if they had done this, it is very likely that they would have concluded that Mr Bashir had not even met Princess Diana before he commissioned the fake documents and showed them to Earl Spencer."

Lord Dyson also accused Lord Hall and Ms Sloman of failing to scrutinise Bashir's account with the necessary degree of scepticism.

The report also said the BBC's suggestion that they had not approached Earl Spencer at the time because he had previously refused to respond to the Mail on Sunday was not a reasonable excuse.

"They never even tried to contact him and invite him to answer some of their questions so as to furnish themselves with the material they needed to test Mr Bashir’s account," he concluded.

Lord Dyson's report also criticised former director-general Lord Birt, who claimed the reason Bashir had been given the benefit of the doubt was because he "persuasive, young and had no form".