Dave King revealed South Africa's authorities have scuppered his plans to stay on as Rangers chairman and lead the club's response to the coronavirus crisis.
Johannesburg-based King says he planned to delay his departure from the Ibrox board in the wake of the global pandemic.
But the 64-year-old has now been forced to leave his deputy - motoring group tycoon Douglas Park - to steer the Light Blues through the turbulent months that now await after he was ordered to enter a 14-day period of self-isolation on his return to the Southern Hemisphere from a visit to Glasgow earlier this month.
King has also confirmed that plans to bring in a fresh round of investment have also been put on hold while the club survey the scale of the damage done to football's finances by the current shutdown.
The Castlemilk-born businessman first announced at the club's AGM in November he would be giving up the role to focus on his interests back in South Africa.
In a statement confirming the end of his five-year tenure, King wrote: "I thank all supporters, club management and the board for the magnificent support I received while guiding the club post regime change to put that specific crisis behind the club.
"It is a great pity that we now find ourselves part of this global crisis. The task team will continue to navigate the club through this difficult time while reporting to the full board.
"The deputy chairman Douglas Park will chair the board during the interim period and a new permanent chairman will be elected by the board at the next board meeting and will be announced immediately thereafter.
"I considered the possibility of extending my time as chairman until the coronavirus crisis is over but that is not practically possible.
"After I returned to South Africa last week from the board meeting, I was mandated by the South African authorities to go into self-isolation for 14 days - which I am presently undergoing.
"Additionally, the South African government does not have the financial resources to offer bailout facilities and it is up to us in the private sector to negotiate arrangements to best survive the months ahead.
"All of my businesses in South Africa are significantly impacted. I decided to pay all employees in full in order to reduce the financial hardship to them. I have also put together a task team that communicates on a daily basis to find ways to make arrangements with landlords, suppliers, creditors and other stakeholders to restructure our businesses for as long as is necessary.
"This is a full-time task that leaves me no free time to make meaningful input to Rangers."
Rangers admitted late last year that they had a £10million short fall in this season's budget.
Far East businessman Stuart Gibson had been reportedly set to inject some much-needed capital into the club.
But now King admits the latest round of investment has been shelved amid the virus panic.
"At my final board meeting in Glasgow on March 14, the board was close to finalising a new round of funding however this has been put on hold while the board considers the financial consequences of the rapidly evolving global impact of coronavirus," he added.
"The subsequent severe developments within the sporting and general business environment - that have now resulted in global lockdowns - has necessitated that the careful financial planning assumptions presented on 14 March are revisited.
"The club has formed a task team that comprises executive management and that reports regularly into the board of RIFC (Rangers International Football Club Ltd).
"The priority of the task team is to ensure the well-being and health of all employees while simultaneously working with fellow clubs, associations, stakeholders and government to ensure that the emotional and financial impact of this pandemic is mitigated as far as possible.
"We presently have extremely limited visibility on how the landscape will develop in the coming months but we'll continue to keep our supporters updated as matters progress. We're all in this together.
"I thank all of my colleagues for the time and effort they continue to devote to our club - particularly when they are all dealing with their own family and business concerns arising from coronavirus.
"It is unfortunate that my stepping down has coincided with the coronavirus crisis but I am relieved that our club has such stalwarts in place to deal with whatever comes our way."