BBC former director-general Tony Hall calls in the lawyers over portrayal in forthcoming Panorama

The BBC’s former director-general Tony Hall has set his lawyers on the corporation – over how he is portrayed in a forthcoming Panorama on the Martin Bashir controversy.

Until last August, Lord Hall ran the broadcaster – now he is understood to have instructed lawyers to fire a salvo at the flagship current affairs programme.

Panorama has carried out an investigation into the way its former star reporter Bashir obtained his famous 1995 interview with Princess Diana.

It has also been probing how former BBC executives, including Lord Hall, handled concerns raised by whistleblowers about Bashir’s rogue tactics.

The explosive Panorama – fronted by BBC veteran John Ware – is expected to be shown next month, ahead of an inquiry report by former judge Lord Dyson. The BBC has commissioned Lord Dyson to investigate claims Bashir spun a string of lies to the princess to clinch his scoop following a series of Daily Mail revelations last year.

The Mail understands that Lord Hall’s legal representatives have contacted the BBC show to ensure programme-makers are aware that he will defend his reputation against any unfair criticism.

It is understood that he and other former executives are concerned about being unable to properly defend themselves because they gave undertakings to Lord Dyson, preventing them from giving their side of the story to Panorama. Lord Hall has been under fire after internal documents revealed he had defended Bashir when it emerged the BBC reporter had commissioned fake bank statements, which it is claimed helped him secure the Panorama interview with Diana.

Former BBC bosses have been interviewed by Lord Dyson as part of his independent inquiry into the events surrounding the famous interview.

It is understood that Lord Hall and others feel that undertakings they have given to the Dyson inquiry mean they cannot talk to the media, including Panorama, about the issue until the former judge has concluded his work.

But some others dispute whether their participation in the inquiry stops them appearing on the programme.

It is understood concerns have been raised to Panorama that programme-makers do not have all the evidence Lord Dyson has and also have not spoken to all of the key individuals.

It is thought that Hall’s lawyer’s letter has effectively put Panorama on notice about treating him fairly and reserves the right to take further action if the programme does not do so.

Lord Hall has found himself at the centre of the controversy about Bashir’s interview with Diana.

After the 1995 interview, he conducted an inquiry into Bashir’s tactics, branded a ‘whitewash’ by critics, which had exonerated the BBC.

Documents released under Freedom of Information revealed how the former BBC chief had backed Bashir after it emerged the reporter had commissioned fake bank statements.

Writing to the BBC board of governors in 1996, Lord Hall had said: ‘I believe he is, even with his lapse, honest and an honourable man.’

But documents from the time also revealed the BBC boss had taken a much tougher line with people suspected of leaking material about concerns over Bashir to the Press.

Lord Hall had said ‘we are taking steps to ensure that the graphic designer involved’ – whistle-blower Matt Wiessler – ‘will not work for the BBC again’.

Lord Hall had also vowed to ‘deal with leakers and remove persistent troublemakers from the programme’.

Last November Mr Wiessler, who was effectively sacked for raising concerns over Bashir in 1996, accused Lord Hall of choosing the ‘scoop’ over the ‘truth’.

Despite the controversy, Martin Bashir was rehired by the BBC in 2016 as its religious affairs correspondent, when Lord Hall was director-general.

The BBC declined to comment.