The remarkable turnaround was brought to a conclusion on Sunday when Steven Gerrard's team were crowned champions for the first time in a decade.

But King – who remains the club's biggest individual shareholder after stepping down from his boardroom role last year – admits he was forced into action after walking away from a face-to-face meeting with Newcastle owner Ashley convinced that Celtic were poised to continue their domination north of the border.

Asked if he feared Rangers would ever disappear completely, the South Africa-based businessman said: "I don't think Rangers would ever have folded completely in the sense the supporters base is so large.

"My view just prior to becoming involved with the club, when I looked at the Easdale/Ashley axis, was that under their business model Rangers were never going to compete for honours again.

"I had a conversation with Ashley in London and his view was that he could run Rangers at a profit.

"He could have done that – of course he could. If you have 50,000 fans willing to buy season tickets then it was feasible.

"If you spend less than you earn and you have a loyal customer base then he could have made a profit.

"But Rangers would never have competed. Rangers at that stage were so far behind Celtic that it required major investment to play catch-up.

"My concern was that if we hadn't found a way to unlock regime change and bring in investors who had the same target of winning leagues and not making money then I felt Rangers would become a senior junior club in Scotland. It would have become a one-team league."

The PA news agency has contacted Ashley for comment.

King – who lost a £20million stake when Craig Whyte plunged the club into liquidation in 2012 – ploughed millions more into Rangers along with his team of investors to pull the Glasgow giants off the floor.

Sunday's title triumph is payback for those efforts to rescue the club but, instead of leaping for joy, King admits he sat back in his chair at his Johannesburg home and took a deep breath as he reflected on the years of struggle to get Rangers back on their feet.

The Castlemilk-born tycoon said: "What does this title mean to me? First it's just the relief as a supporter that the project we all embarked on a few years ago to try to get back winning championships has been finished.

"To do it in such style really gives me an immense sense of satisfaction as a supporter.

"Additionally to me as an individual given my role in the whole regime change process and trying to get the club back to this point and the commitments I made to supporters that we will do everything we can to get back to number one, that gives me a lot of personal satisfaction to have finally achieved that.

"There were definitely points where I realised the challenge of getting back to winning league titles was more difficult than I'd assumed – and I must say I assumed it would be quite difficult to start with.

"Where I realised what I thought was a big challenge was even bigger than I first thought was after (the) regime change. It was then that I realised the level of disintegration of the infrastructure.

"It wasn't just the football team. We understood the team couldn't win without the proper infrastructure.

"But the stadium neglect was palpable but there was even more basic things like coaching and sports science. We had nothing in place.

"So it wasn't just a question of working on the football team. We also had to manage a lot of our financial resources into areas away from the team that I hadn't anticipated.

"So my challenge was how to manage the non-footballing infrastructure issues in a way that didn't compromise the football.

"That really just meant having to raise a lot more money than I'd initially hoped for.

"There were a lot of challenges and it affected me in terms of timeframes – but never to the point where it made me lose belief that we would win a title. It was just a case of what year."