Britain's Prince Charles personally accepted a suitcase filled with €1m in cash from a senior Qatari politician, according to reports.
The heir to the British throne received a total of €3m from Sheikh Hamad bin Jassim Al Thani during their private meetings between 2011 and 2015.
The money was deposited to the Prince of Wales's trust, which he uses to fund charitable initiatives and other personal projects.
A representative for Prince Charles said there was no wrongdoing on the prince's part and that “correct processes” were followed when the donations were made.
The newspaper claims that Sheikh Hamad, 62, presented the prince with €1m in carrier bags from the Fortnum & Mason grocer during a face-to-face meeting.
In another meeting, Prince Charles is believed to have met the sheikh at Clarence House in London where he accepted a holdall containing another €1m.
According to reports, two advisers in the royal household then hand-counted the cash which was in €500 notes, a denomination that is now discontinued.
Employees of private bank Coutts collected the money from Prince Charles' residence and deposited the money the Prince of Wales Charitable Fund.
Britain's royal family is banned from accepting gifts of money in connection with an official engagement or duties — but can accept a cheque as patron of, or on behalf of, a charity.
“We are disappointed not to have been given more time to look into this matter, which dates from a decade ago,” a Clarence House representative said.
“At a few hours’ notice from The Sunday Times, we have checked into this event in the past, and confirm that the previous trustees of PWCF discussed the governance and donor relationship, [confirming that the donor was a legitimate and verified counterparty] and our auditors signed off on the donation after a specific inquiry during the audit. There was no failure of governance”.
Coutts said it cannot comment client affairs.
“We have long-standing and robust policies and controls to assess the source, nature and purpose of large and unusual transactions.
“In particular, receipt of cash payments by the bank receive thorough review and oversight.”