Prince Charles's charitable foundation has come under the radar of the Office of the Scottish Charity Regulator (OSCR) after reports emerged that it was involved in a cash-for-honours scandal on multiple occasions.

OSCR confirmed earlier this week that it was investigating one of the royal's charities upon taking cognisance of a report in The Sunday Times that claimed he wrote a thank-you letter to Russian banker Dmitry Leus after receiving a large donation for The Prince's Foundation in May last year. The newspaper had released another report earlier this month that Charles's closest aide Michael Fawcett had offered to help Saudi billionaire Mahfouz Marei Mubarak bin Mahfouz obtain British citizenship and honours in exchange for a massive donation.

In Leus's case, he had reportedly been seeking British citizenship, and made his donations to Prince Charles's charity after a fixer promised to arrange a private meeting with the royal at a Scottish castle. The Prince of Wales then wrote to Leus that he was "incredibly grateful" for this "immense generosity" that has brought him "great comfort." However, there is no evidence that the heir apparent was personally aware of any deception around the donation.

Meanwhile, the banker had been charged in Russia of money laundering, but was later acquitted of the charges. At the time, the charity's ethics committee raised concerns about his background, following which his donations were reportedly diverted to Children & the Arts, another charity of which Charles is a patron.

Leus's spokesperson clarified to CNN that his conviction was struck out in 2007 and he "has a completely clean criminal record" now. The representative also confirmed that the banker had made "two separate donations together totalling £500,000" to the Prince's charity via a fixer, the Burke's Peerage, but he has only now learned that not all of these funds were then forwarded on to the Prince's Foundation.

"No funds at all were returned to him from Burke's Peerage. Mr. Leus did not know of, or consent to, his donation being transferred to the Children's Arts Foundation [and other organisations]. Had he been consulted, he would have chosen to use the money to help the many vulnerable children and young people that the Leus Family Foundation supports across the UK," the spokesperson said, adding that donations were meant to support the foundation's "educational and heritage goals," particularly to create a "National Fencing Centre."

Douglas Connell, chair of The Prince's Foundation has insisted that it is taking the allegations "very seriously," and a full review is expected to take several weeks.

Meanwhile, OSCR has written to the foundation's trustees informing them they would investigate the claims around Leus's donations, and that they have been working with the charity to get a better understanding of its funds and work.

"We have written to the trustees informing them that we will investigate these matters under the powers set out in section 28 of the Charities and Trustee Investment (Scotland) Act 2005 and will follow up any additional queries as they arise," it said.

Prince Charles
Prince Charles Chris Jackson - Pool/Getty Images