"All farewells should be sudden, when forever." It is the sentiment behind that Lord Byron quote that Sir Alex Ferguson has always maintained would guide his decision over when to quit as manager of a club that he has triumphantly, righteously moulded in his own image for 27 dominant years.
The latest round of rumours that the 71-year-old is considering his future despite having given no prior warning would fit with the promise he made to himself in 2002, when the gut-wrenching thought of quitting Old Trafford caused him to make a very public U-turn on a pre-season decision to retire at the end of the 2001-02 campaign.
He considered the decision an "absolute disaster". An acute feeling of "agony" at the thought of no longer being immersed in life at Carrington and the intervention of his wife Cathy – "I think she thought she would soon be fed up with me around the house" – made him reconsider the following February.
A lingering feeling that his decision to make the announcement well in advance, well intentioned at the time to allow for succession planning, left his squad lacking in hunger and contributed to a rare trophyless season was behind his resolution to make any decision to retire a sudden one.
Last October, it was the turn of Manchester United's incoming chief executive Edward Woodward to confront the question that has stalked the thoughts of the club's executives for more than a decade and has preoccupied everyone from Wall Street investors to millions of fans at home and abroad.
It is one that has obsessed the successive regimes that Ferguson has worked under from Martin Edwards to the PLC era and then the complex financial modelling and constraints of the Glazers.
And it is a question that Ferguson himself has been answering at least since he celebrated his 10th anniversary in charge in 1996, just four years into the Premier League era. "The notion of a retirement age is anathema to me. There should be a law against it. The calendar can't decide how alert or vigorous a person is. I felt good at 55 and I was up being pestered about when I was going to retire," he recorded in typically forthright fashion in his autobiography.
But it is the one question that, for all the millions pouring in and all the control modern football clubs are able to exert over the minutae of their operations from sports science to scouting, the club's hierarchy could not answer.
"A plan has been thought through as regards the type of person and the process and it's in a drawer. There is no ongoing conversation," Woodward told the Guardian last October.
You can bet it has been dusted down by now. And while Ferguson may favour a man in the mould of Everton's David Moyes, a manager whom he clearly admires and perhaps can see something of himself in, might the club's owners favour a more proven European performer whom they may consider would provide more certainty that the cash registers would keep ringing from Boston to Bangalore?
That question was posed to Woodward in the club's Mayfair sales offices before Pep Guardiola had made it clear that Bayern Munich was his destination of choice and prompted by the knowledge that it may be a long time before there would be a summer with so many top managers on the market.
Guardiola aside, the possible availability of José Mourinho and Jürgen Klopp had alerted the world's biggest clubs. And yet there was an acknowledgement that there could be no active discussion until Ferguson, who has this season delivered his 13th league title at Old Trafford and the 49th trophy of his career, indicated his time was up.
The Scot's own statements on the matter have been contradictory. He has informed that he would only ever retire through ill health, but in March said: "There's no getting rid of me. I will probably become a director. Nobody knows. Neither do I. It won't be a doctor that tells me to quit."
In many ways he has seemed more at home under the Glazers, despite the constraints on his budget, than he was amid the vagaries and personality clashes of the Edwards and PLC eras.
He and the chief executive, David Gill, are largely left alone to run the football operation, with Ferguson holding strict sway over the playing side, and their relationship should never be underestimated as a key ingredient in the club's ongoing success. Gill will move aside this summer to allow Woodward to take over as chief executive but will remain on the Manchester United board.
It was once made clear to Ferguson that he would not be encouraged to hang around at Old Trafford after his retirement for fear of repeating the "Sir Matt Busby syndrome", where the continued presence of the club's legendary manager was seen to have had a disastrously debilitating effect on his replacement.
But he has long since outlasted anyone at the club who holds that view and should he decide to call time as manager there would be a rush to offer him an ambassadorial role. He has professed admiration for the role Sir Bobby Charlton plays at Old Trafford and the way Bayern Munich have managed succession planning and kept the club's biggest names involved.
It is perhaps appropriate that the latest round of speculation over his future should coincide with a renewed bout of soul searching at the Emirates over if and when Arsène Wenger will move on.
For all that Ferguson has continued to deliver trophies while Wenger has foundered of late, they are likely to be among the last of their kind – men who through sheer force of personality, longevity, obsessive dedication and talent for reinvention ensured their personality and style seeped into every corner of two of English football's biggest institutions across successive generations of players and fans.It is one reflection of how far football has changed since Ferguson was appointed manager of Manchester United in November 1986 that, under Wall Street rules, clarification of Ferguson's position will have to be announced to the New York Stock Exchange where a tranche of shares in the club was floated by the Glazers last year.
There has, at times, been a valedictory feel to Ferguson's 13th championship-winning season at Old Trafford – the statue, the naming of the stand. But on other nights, such as when the club exited the Champions League to Mourinho's Real Madrid after Nani's controversial sending-off as Ferguson railed furiously on the touchline, it has been hard to imagine that he would take his leave so soon.
"There obviously will be a point when I do quit and when it is I absolutely have no idea because I tried that, and it was an absolute disaster," said Ferguson in 2010. Three years later, with another Premier League title won and the pretenders from Manchester City vanquished to add to the long list of foes he has seen off, has he abruptly decided on a sudden farewell?
guardian.co.uk © Guardian News and Media Limited 2010
image: © Andrea Sartorati