Three weeks ago, the director of BBC Northern Ireland was pictured beaming from ear to ear while he supervised the end of an era as analogue television disappeared with the flick of a switch.
On a board behind him were emblazoned the words ‘Television — past, present and future’ and they called the expensive extravaganza The Magic Box.
Mr Johnston has now found himself in the Pandora’s Box which has been opened in the remarkable and unprecedented furore over a BBC Newsnight programme which wrongly — and carelessly — accused top Tory Lord McAlpline of child abuse in North Wales in the 1980s.
Heads have already rolled inside the corporation over the programme and Monday dawned with the 45-year-old former rugby player from Ballymena named as the latest BBC executive to be embroiled in the sensational row.
It was revealed that Mr Johnston, six years in the top job in Ormeau Avenue, had a role in the Newsnight shambles.
The Daily Mail described Mr Johnston, who’s reported to be on £150,000 a year, as “obscure” and said he was put in the position of overseeing the decision to transmit the erroneous report because the BBC had run out of people from its management board to do so.
Mr Johnston sits on that board at national level and was one of a number of members who shouldered new responsibilities after other senior executives stood aside from decision-making in the wake of the shelved Newsnight programme about allegations of child abuse against TV and radio star Jimmy Savile.
For most of Monday, Mr Johnston was involved in discussions about the latest twist in the Newsnight saga which over the weekend forced the Director General of the BBC, George Entwistle, to resign after only a short time in the job.
Bizarrely, Peter Johnston’s own employees in the BBC Northern Ireland newsroom were left in the dark about his position and reported that he and the corporation weren’t making any comment.
Every hour it appeared that there were more dramatic developments and more senior officials leaving their jobs, albeit temporarily.
Then came a hastily completed report from the director of BBC Scotland Ken MacQuarrie about what had gone wrong with the Newsnight debacle as he tried to establish the circumstances and editorial failings around how journalists got it so wrong about Lord McAlpine.
MacQuarrie said that there was ambiguity around who was taking the ultimate editorial responsibility for the Newsnight programme, especially in the days leading up to its screening 11 days ago.
The next chapter in the fastevolving story came as the BBC issued a statement on Monday evening that Peter Johnston “was involved in decisions” about the Newsnight programme.
But that wasn’t the end of it all. Peter Johnston broke his silence on Monday night outside Broadcasting House in Belfast.
He was asked if he was considering his position. He replied: “No, I am not.”
Mr Johnston confirmed that he had been involved in decisions about the Newsnight report and added that he had “great faith” in BBC journalism.
Ironically, in Belfast on Monday, the Society of Editors held its annual conference in Titanic Belfast and there were discussions about whether or not the Newsnight programme could survive in its present form.
Given the surroundings it was hardly surprising there were also whisperings about people going down with a sinking ship…
The BBC began disciplinary proceedings against its own staff on Monday night after admitting that “basic journalistic checks were not carried out” by its flagship programme Newsnight, and that “unacceptable failings” in editorial procedures had led to the Tory grandee Lord McAlpine being falsely linked to a paedophile ring.