Labour MP Austin Mitchell accused the Prince of “dodging around” for tax purposes and he is one of many MPs who had “concerns” over the Prince’s spending, according to author Tom Bower.
The National Audit Office undertook the first official investigation of the Royal family’s accounts after the death of the Queen mother.
Tax officials would have asked for millions inheritance tax on her jewels and art collection but they were told she gave them to her daughter and grandchildren in 1993 and by law gifts made seven years before death are not liable to inheritance taxes.
But after the investigation of some of the family’s accounts, the national audit office concluded that there were “obscurities and potential conflicts of interest” in the accounts of the Duchy of Cornwall - which in 2004 was providing Prince Charles an income of £11.9million a year.
The Public Accounts Committee launched an investigation and one aspect that was of concern was for £2.3million of trees to the duchy itself - which were planted for Charles on Duchy land.
In this deal, it is alleged that the Prince took the money without paying any tax.
His advisers also boosted his income by moving money from the duchy’s capital account to the revenue account and refused to detail the reasons.
Mr Bower said the reason is alleged because Charles wanted more money, perhaps to pay his staff.
The majority of his staff members made little dent in his income because 94 out of 124 were described as “official” employees which means they could be claimed against expenses against tax.
MPs are also said to have questioned the claim of Camilla’s personal upkeep as a tax deductible item.
This included hair, clothes and jewellery even though she undertook very few public duties.
But when questioned on this matter, Charle’s private secretary Michael Peat resisted giving detailed answers.
He claimed the duchy’s arrangements had been secret for 700 years and outsiders had no right to know about them, but apparently MPs remained unconvinced - it is claimed.
Charles used his spokesman to describe the committee’s report as a “travesty” and “fundamentally wrong”.
The Chancellor of the Exchequer at the time, Gordon Brown, defended him and said: “He does not deserve to be the target of these shoddy and underhand tactics.”
But Charles’s income kept rising and the 2008 stock market crash did not affect him.The year before it is claimed his advisers sold off most of his shares.
That year Charles also increased his staff to 146 including nine media specialists and 11 gardeners.
By 2009 his income was £17.1million even though the rest of the country was suffering, it is claimed.
In 2013, the Public Accounts Committee grille Prince Charles over his principal private secretary over corporation and capital gains tax exemptions enjoyed by his duchy estate.
But Charles had used the Human Rights Act to prevent anyone having access to his tax returns.