DAVE King, the Rangers chairman and majority shareholder, needs to make a bigger investment or move aside if the club can ever hope to bridge an increasingly large gap to Celtic, according to Maurice Johnston.

One of Scotland’s most colourful and controversial figures, in a rare return to Glasgow, backed the credentials of new manager Pedro Caixinha but insisted his old club would remain miles behind their rivals unless money was found from within or outside of Ibrox.

Johnstone, who of course played for both sides of the Old Firm, was singing from the same hymn sheet as Walter and Ally McCoist, both of whom have recently argued that only money and lots of it could take Rangers back to the top.

King on Monday revealed he could face a bill close to £14 million because a ruling stated he had to make an offer to buy shares in Rangers International Football Club PLC after it was decided the South African businessman acted with others to win control of the boardroom.

And if he doesn’t have the money or the will to put more into Rangers, then Johnston believed a change at the very top might be the only answer.

“I have no idea how you solve the money problem,” said Johnston who has lived in North America for almost 20 years. “It’s a really tough one. If Rangers are going to have any chance of challenging Celtic, they need to spend the cash. I know it’s not there right now but that’s what they need.

“I don’t think the fans will accept being second. They will only accept Rangers winning the championship.

“The problem for Rangers is that Celtic are streets in front of them in terms of the finance side. If they get £30m from the Champions League or selling Moussa Dembele, for example, then that takes them even further away.

“I don’t know the boy King’s finances but if he puts more money in then things might improve. But I don’t think he’s going to do that. If this is the case then, probably, they would need someone else to come in and invest their money.

“There aren’t a lot of people out there who would be able to do that. For me, it would have to be someone from China.

“I believe Caixinha will be fine. He has a good CV and did well at the clubs he’s worked at, which are all at a decent level. However, he needs money.”

Several English clubs in both the Premier League and Championship have been taken over at least partially by foreign owners with Chinese investment becoming increasingly prevalent over the past 18 months.

But whether Scottish football enjoys a big enough profile to attract serious investors from the Far East is up for debate.

“Listen, Rangers are a big, big club,” said Johnstone. “They both are. If you get it right, you’ll get your money back. The amount of money going about the Champions League is ridiculous, and that is what they’re striving for, but right now they are not even close.”

A former Scotland colleague of Johnston’s, Charlie Nicholas, last month claimed that Celtic would win the league until the day he died.

It is difficult to see six in a row, which could be sealed as early as this Sunday, not being added to over the next number of years “It’s hard to say that Celtic can never be caught,” said Johnston. “If someone does come in with a bit of money, which would mean better players going to Ibrox, then Rangers will challenge them. Right now, that’s not going happen.

“A different coach will bring a different mind-set and, with some investment, you just never know.”