A SIGNIFICANT institutional investor in Rangers has called on Charles Green to surrender his £2.8 million shareholding and leave the board immediately, claiming he has brought the club into disrepute.

The investor has also called on the board of Rangers International Football Club to realign itself around chairman Malcolm Murray, declaring it bought shares on the strength of Mr Murray's City background and lifelong support of the club.

The institutional investor, speaking on condition of anonymity, declared it had never seen scandal engulf a company so soon after a flotation.

A senior executive at the investor said: "Within four months of the IPO [initial public offering], we have this scandal."

The investor has been upset by allegations of links between Mr Green and former Rangers owner Craig Whyte, who was at the helm when the club collapsed into insolvency last year.

Mr Whyte claimed he was behind the new company that bought the assets and business of the club from liquidation.

Mr Green denied he had been Mr Whyte's "front man" and claimed he and former Rangers commercial director Imran Ahmad had told him what he wanted to hear as they needed his co-operation to acquire shares if the club had secured a Company Voluntary Arrangement.

Mr Green has cast doubt on the validity of documents that appeared to show he had signed off the appointment of Mr Whyte and his associate Aidan Earley as directors of Sevco 5088, the company that bought the assets of Rangers for £5.5m in June last year. They were transferred to a separate company, Sevco Scotland, days later.

The executive at the investor said: "We invested in this at the IPO because we thought it was a good business. With Malcolm Murray as the chairman, we thought it was going to have good governance - I was at a presentation when Green was asked specifically if he had any relationship with Whyte, and he denied any.

"When we further analyse it and find Green got his five million shares for nominal value, we feel he should be giving them back. All he has done is bring disrepute to the club. His efforts have been negative. Malcolm Murray is a good, independent guy. The board should realign around him and Green should leave immediately."

Mr Murray is believed to have lost a vote of no confidence among the club's directors this week.

Rangers said last month Mr Green wished to step down as chief executive with immediate effect and leave the company by the end of May. The institutional investor has a stake of about 1% in Rangers, which is worth several hundred thousand pounds.

A club spokesman said: " If an institutional investor feels this way, then they should make their feelings known to the club. There is an ongoing independent inquiry into alleged links between Mr Green and Craig Whyte. Mr Green strenuously denies any wrongdoing and the club hopes the inquiry will be completed shortly."