Michael Fawcett, the Prince of Wales’s former royal valet, had temporarily stepped down as chief executive of The Prince’s Foundation in September while the charity investigates his actions.
A spokesperson for the charity said he has since resigned from his post.
Mr Fawcett and his party planning firm, Premier Mode, will also no longer be providing services to Clarence House, a spokesperson said.
A spokesperson from the foundation said: “Michael Fawcett has resigned from his post as CEO of The Prince’s Foundation.”
A Clarence House spokesperson said: “Michael Fawcett and Premier Mode will not be providing services to us in the future. We have all agreed to end these arrangements”.
It follows reports Mr Fawcett allegedly promised to help secure a knighthood and British citizenship for a Saudi billionaire after he donated £1.5m to restoration projects of particular interest to Charles.
The Sunday Times and Mail On Sunday both reported that Mr Fawcett had coordinated support for an honour to be given to businessman Mahfouz Marei Mubarak bin Mahfouz.
Mr Mahfouz, 51, who received an honorary CBE in 2016, denies any wrongdoing. (Sky)