Both William and his brother the Duke of Sussex issued strongly worded statements following the publication of Lord Dyson’s blistering report last month, which criticised the methods used by the BBC journalist to obtain his exclusive 1995 interview with the princess.
Appearing before the digital, culture, media and sport committee on Tuesday, Lord Hall said he had not since spoken directly to William to express his remorse.
He said: “We did what we thought was right at the time, investigating Martin Bashir not once, but twice.
“I have a huge amount of respect for the prince. I’ve worked with him on various things in the past and I’m deeply sorry for the hurt that this has caused to him and I do want to make that clear.”
Asked if he had spoken to the prince, Lord Hall added: “No I haven’t. I wanted to have that session with you all before I think about what I do next.”
Lord Hall, who was director-general of the BBC from April 2013 to August last year, also led a 1996 internal inquiry into how Bashir secured his bombshell interview with Diana.
He admitted it had been the “wrong judgment” to believe the journalist was remorseful for his actions and allow that to influence the final decision.
Asked why he had subsequently reported to the board of governors that Bashir was an “honest and honourable man”, Lord Hall said: “In the end we came to a judgment about his lack of experience, that he was out of his depth, that he was contrite, and we gave him a second chance.
“We trusted him and it turns out we couldn’t.
“In that light, I understand I am using words which when you look at them now just seem wrong.
“But it was me trying to work out ‘could I trust this man or not?’”
Lord Hall said Bashir was quizzed during the internal investigation for an hour-and-a-half and he was “in tears”.
A review into the decision to appoint Bashir as religious affairs correspondent at the BBC in 2016 following the interview found “no evidence” the journalist was given the job to “contain and/or cover” up the events surrounding the programme and that Lord Hall did not play a part in the decision to rehire Bashir.
Committee chairman Julian Knight said it was “utterly extraordinary” the BBC would rehire Bashir and asked how it came to be that a “known liar” was brought back to the corporation.
Lord Hall said he was not going to second guess the people who were filling the role. He said: “If we knew then what we know now, of course he wouldn’t have been re-hired.”
Mr Knight said: “A cynic would suggest the process was entirely concocted so that the resolution at the end of the day was that Mr Bashir would get this job.”
The BBC has since apologised to the whistle-blower who tried to expose Bashir’s methods.