Sir Angus also criticises the "culture of leverage" in the financial sector in his chairman's statement on the latest accounts of his Noble Grossart Holdings merchant bank, which have just become available from Companies House. These accounts show a rise in pre-tax profits to £8.27 million in the year to January 31, from £8.01m in the prior 12 months.
Sir Angus describes the year to January 31 as "satisfactory" for Noble Grossart, which has investments in companies including Falkirk-based bus manufacturer Alexander Dennis and dental products firm Wright Health Group.
He declares that Noble Grossart's balance sheet, which shows a rise in net assets to £92.9m at January 31 from £88.2m a year earlier, "confirms our very strong and liquid position".
In his statement, Sir Angus writes: "The last five years have revealed the true effects and costs of balance sheets which were allowed to become exposed to undue downside risks.
"Unbalanced risk management concentrated on the upside potential. Voices and perspectives, experienced on the dangers from previous downside cycles were unheard, until the wolf did arrive at the door."
He adds: "The culture of leverage was endemic, sponsored by governments, endorsed by regulators, and approved by analysts and investors. It is not surprising those with no hinterland of experience thought the band would play on as the waters rose on the doomed ship."
Sir Angus highlights the impact of changes in accounting rules over the last decade, specifically a move towards valuing assets at market value, rather than at their cost or written-down value.
He says: "The pervading culture (of leverage) was also encouraged, no doubt unintentionally, by the accounting acceptance of 'marking to market'. This had the con-sequence, which seemed bizarre to many, that unrealised profits started to appear in the profit and loss account.
"It did not take long before opportunistic cats began to enter that particular fish shop.
"Accounts could plausibly be agreed to be accurate, but were they therefore reliable?
"There is much accounting and financial theology to justify what ought to be intellectually correct in this field, but too few voices to remind us that reliable simplicity should be the better result. We can ask whether anyone, in planning their domestic finances, would have conducted their own affairs on a similar theoretical basis."
Sir Angus contrasts the "mark to market" practice with his own firm's accounting policies.
He says: "We have always carried our assets at their cost, or written-down value. This has stood the test of reliability, in good and in difficult times.
"It reflects our long-term and hard-headed approach to our business, and is a navigational beacon which continues to guide us well in times of continuing uncertainty."
Asked to elaborate on the context of his comments in the accounts, Sir Angus described the move to "mark to market" accounting treatment as "particularly unhelpful territory".
He added this had had a particular bearing on financial institutions and also affected other companies, such as property groups. He did not name any individual financial institution in relation to his comments on accounting policies.
Sir Angus said: "There is a complex (accounting) theology which has evolved and expanded each year, so it has become more and more esoteric and I believe more and more detached from a real view as to a company's progress or condition.
"I think it is like an intellectual virus – once it starts growing it is very difficult to stop.
"It is evolved by clever people but I fear they lose sight of the reality test."
Sir Angus, meanwhile, kept his powder dry on the Scottish independence debate, declaring: "The Grossart Party has not yet published its manifesto."