Rangers have been forced to wait another season for the Premiership return. Jeff Holmes/EMPICS Sport

Rangers chairman David King will hand the next Ibrox manager a multi-million-pound war chest after promising to spend "whatever it takes" to guarantee the club's Scottish Premiership return next season.

The Gers face another 12 months in the Championship after their humiliating 6-1 aggregate playoff defeat to Motherwell and the task now for King is to find the man who can lead them back to the top-flight.

After that, his task will be to help the manager recruit a whole new team after 11 out-of-contract players were told they were free to go.

While King has not ruled handing interim boss Stuart McCall a new deal, the Castlemilk-born tycoon did reveal Rangers have touched base with five candidates for boss, with an announcement likely next week.

He said: "There are possibly five realistic candidates that might fit the bill. It is very important we balance the obvious urgency of making an appointment with the need to get it right.

"We need to make an appointment that sees us through for the next three years."

The Johannesburg-based businessman -- back in Glasgow to launch a five percent increase in the club's season-ticket prices -- had previously stated it could take £30 million to put the club back on an even keel with Celtic.

Now he claims the spread of that cash will have to be front-loaded to ensure the club do not let another 12 months fritter away.

"I think we will need money now because we will need to beef up the squad," he said. "So there will be a fairly substantial investment required in the next couple of months from me and the other investors.

"But if you want to look at the funding plan, it is to spend whatever it takes to win the Championship next year and have at least the nucleus of a squad to move up to the Premier League the year after.''

He added: "The mandate to the manager is going to be, 'do not get players who will help us win the Championship -- get players that could compete in the Premier League.'"

For many, King's words will bear a resemblance to former owner David Murray's infamous claim that "for every fiver Celtic spent, he'd put down a tenner."

It was that kind of flagrant spending which saw Rangers eventually sink into a financial blackhole.

But King insists the new board will have to live dangerously in the meantime if they are to solve the club's current loss-making problems.

"We're going to increase running costs at the club," he said. "The idea is to have it sustainable by the end of the three-year period -- not during it."

Rangers fell to a damaging 6-1 playoff defeat to Motherwell to miss out on promotion this season. Jeff Holmes/Getty Images

While King claims Rangers will spend big this summer, he refused to put a figure on how much he would personally put into the club as he admitted factors such as their controversial Sports Direct retail deal and the £5 million loan taken out from the sportswear company's owner Mike Ashley could put hurdles in his way.

"That hasn't changed," he said when asked if £30 million was still the sum required to end the turmoil Rangers have been living through since their 2012 liquidation.

"The only thing that has changed in my own personal thoughts over the last couple of weeks is the acceleration of that.

"I think it is very important that we win the league this year, so it's probably the right thing to over-invest this season and make sure we do comfortably come out of the league and have a strong squad going into next season.

"The funding figure of what will be required is based on a number of things outwith our control. It would depend on our ability to renegotiate the commercial arrangements, the level of season-ticket uptake, whether we repay the £5 million loan.

"So the investment must be whatever it takes to comfortably win the league and substantially take us forward into the following season."

Former Brentford boss Mark Warburton has held "informal talks" with Rangers about replacing McCall but King admitted other bosses had been turned off the idea of managing the club by the prospect of another year in the Championship.

But despite the failure to reclaim their Premiership slot, King -- who says the club are hoping to be re-listed on the ISDX stock market in October -- thinks the task of one day catching Celtic will be made easier by an extra season in the second tier.

He added: "I don't think catching Celtic has been made harder by the Motherwell result. It's been delayed by a year but I think it's now easier.

"To have gone up this year with a new management team and virtually a whole new team would have been very hard. At least now we have three transfer windows so we can get the new management structure settled in."