The Crown Office and Procurator Fiscal Service ultimately admitted wrongdoing over its prosecution of former Rangers administrators David Whitehouse and Paul Clark of Duff & Phelps, along with other businessmen connected to the club. The civil claims were settled out of court, with more than £50 million paid in compensation.

The settlement was agreed by then Lord Advocate James Wolffe. However, the Sunday Mail has revealed that his predecessor, Lord Mulholland, now an Inner House judge, challenged the decision in an email sent to Mr Wolffe.

Lord Mulholland wrote: “The evidence in this case points to fraudulent behaviour on the part of all accused involving many millions of pounds… I have underlined the word ‘all’ for emphasis.

“This is why I expressed surprise (now incredulity) at the decision to settle the case on the basis of a malicious prosecution and all the reputational damage that flows from such a decision.”

Mr Whitehouse, Mr Clark, former Rangers owner Charles Green, businessman Imran Khan and David Grier were all prosecuted in connection with the club’s collapse. Charges against all five were eventually dropped, and all except Mr Grier later succeeded in malicious prosecution actions.

In the email, Lord Mulholland maintained that the decision to prosecute had been justified. He referred to an internal Duff & Phelps email stating: “We are not broadcasting involvement to anyone in case guy who has bought it, our client, makes a mess of the whole thing. We don’t want to be associated too heavily.

“The guy who bought hasn’t got a f****** clue - no plan, no strategy, did very little DD (due diligence) - it is honestly baffling.

“He only went ahead and did it as hasn’t risked any of his own cash - paid £1 for shares and funded repayment of bank debt by forward selling three years’ worth of season tickets revenue. So everyone thinks he is a saviour but in fact it is all a big front and club has as much debt as it had before, just to someone else.”

Rangers was sold by David Murray to Craig Whyte for £1 in 2011 before entering administration the following year. Following the club’s liquidation, Charles Green acquired its assets for £5.5 million through a new company.

A public inquiry into the handling of the investigation has been promised but has yet to begin.

Mr Whitehouse told the Sunday Mail: “The attempt by Mulholland to obfuscate responsibility for his behaviour shouldn’t surprise anyone, desperate people say desperate things. It is equally unsurprising that his desperate requests were ignored by those in charge at the time.

“What is of greatest importance is that the long awaited promised public inquiry takes place without further delay, as this is the forum which will fully expose all the facts, many of which are well known to both me and Mulholland. This is the forum which will lay bare the scandalous behaviour of the Crown Office and particularly Frank Mulholland.”

A COPFS spokesperson said: “Following a detailed review of the case, the Lord Advocate accepted that there had been significant departures from the normal practices designed to ensure prosecutions are brought on a proper basis.

“The Crown supports a process of inquiry into what happened.”