The former director of group security for News International (now News UK), publisher of The Sun and The Times, has posted a video to YouTube threatening to tell "everything I know" about wrongdoing at the company.
Mark Hanna stood trial along with seven others in connection to the phone hacking scandal which led to the closure of the News of the World and to the resignation of Rebekah Brooks as News International CEO.
Despite being acquitted of wrongdoing at the climax of the eight-month trial, Hanna was made redundant with a payout he claimed was less than £30,000.
Hanna's YouTube statement was, he said, prompted by the return of Rebekah Brooks, who received a £16 million payout when she resigned as News International CEO, to "the Murdoch umbrella". It was revealed last week that Brooks, a former editor of both The Sun and News of the World, is to return as CEO of News UK on Monday.
Hanna was scathing about Brooks' return.
"As some have quoted this is two fingers up to the nation and those that were victims of the company's illegal activities," he said in his two minute 30 second video, which appeared to be shot using his phone.
"To me, her previous director of group security, it is Murdoch's middle finger being shoved right into my face after standing trial with her and others in what was classed as the trial of the century during which it was widely accepted that I should never have been involved."
Brooks, like Hanna, was acquitted of all charges.
Hanna then made a series of allegations that senior executives had ignored warnings of wrongdoing at the company.
"I am now standing up against those who would sit back and treat us all with contempt, the Murdochs and Brookses of the world," he said. "Very soon, I intend to make it known just how underhanded they have been and despite whistleblowing by myself they have ignored numerous warnings of potential illegal activity."
Hanna continued: "I intend to tell you everything that I know, which I'm sure will shock everybody as well as revealing what it was like working in what was, or is certainly becoming, one of the most hated organisations in the UK, if not the world.
"From the day I joined the company, things were not right, from dealing with intrusive surveillance to unclear payments, having always been law-abiding and doing things by the book, I aired my concerns to the relevant management but was always told to ignore things.
"As time went on, more things came to light, and again after reporting them and airing my concerns about potentially illegal activity, which are classed as protected disclosures, I was told just to carry them out without regard as to who it involved."
At the time of publication, News UK had not responded to a request for comment from BuzzFeed News, though a spokesman indicated the company was aware of Hanna's video.
You can watch Mark Hanna's full YouTube video below
View this video on YouTube
A spokesperson for News UK said: "Mark Hanna has been through an exceptionally difficult time. He was acquitted in court and, throughout the trial, we supported him and paid his substantial legal fees. We also continued to pay his salary and bonuses and provided other financial support throughout his trial and afterwards. When he said he wished to return, we offered him a comparable position with the company.
"Despite all our efforts to find a resolution with Mark, the matter is now before an employment tribunal, a fair and independent proceeding, where the company will defend itself vigorously. We consider his YouTube video to be an attempt to force News UK into offering an unreasonable financial settlement. Of course, we completely reject his accusations of illegal conduct."