One of Prince Charles’s closest aides has stepped down from his role following claims he offered to help secure an honour for a rich Saudi donor.

Michael Fawcett, a former assistant valet to the prince, has temporarily left his job as chief executive of The Prince’s Foundation, the charity confirmed on Saturday.

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, was given a CBE by Charles in a private ceremony at Buckingham Palace in 2016, The Sunday Times said, after paying “tens of thousands of pounds to fixers with links to the prince who had told him they could secure the honour”.

The newspaper quoted leaked correspondence from William Bortrick, the owner of Burke’s Peerage and one of Mr Mahfouz’s advisers, telling colleagues in 2014 that once the Saudi had “Hon OBE… then more money will flow”.

The OBE, he said, was “promised” to Mr Mahfouz “to get the £1.5m he paid for Dumfries (House) and (The Castle of) Mey”.

He added: “MF (Michael Fawcett) needs to keep to his side of the bargain and sort out the Hon OBE immediately – then assist with citizenship.”

The Sunday Times said Mr Fawcett later helped to “upgrade” the proposed honour from an OBE to a CBE.

Douglas Connell, chair of The Prince’s Foundation, said: “Earlier today, Michael Fawcett offered to step down temporarily from active duties as chief executive of The Prince’s Foundation while the trustees’ investigation is ongoing.

“The Prince’s Foundation has accepted this offer.

“Michael fully supports the ongoing investigation and has confirmed that he will assist the investigation in every way.”

It is understood that Emily Cherrington, chief operating officer, will take over meanwhile, and that the Scottish Charity Regulator (OSCR) has been informed as The Prince’s Foundation is registered in Scotland.

But some have called for more – among them, former Liberal democrats MP Normal Baker, who told Sky News he wants the Metropolitan Police to investigate allegations of cash for favours, including honours concerning Mr Fawcett.

Mr Baker wrote in the Mail: “It is the Prince of Wales, not Michael Fawcett, who has to answer questions now. His royal fingerprints are all over this.

“The monarchy has been seriously damaged by the dodgy activities of the boorish Prince Andrew and by the self- obsessed bleatings of Harry and Meghan.

“The Queen continues to command respect, but she will not go on for ever.

“This morning, many will be asking themselves how Prince Charles can square such behaviour with the momentous responsibilities he is due to inherit one day.”

A spokeswoman for The Prince’s Foundation said: “The Prince’s Foundation takes very seriously the allegations that have recently been brought to its attention and the matter is currently under investigation.

“We are incredibly proud of The Prince’s Foundation’s charitable work and the positive impact it has on our beneficiaries throughout the UK and across the world.”

Mr Fawcett was appointed footman to the queen in 1981 and rose through the ranks to become Charles’s assistant valet.

In 2003 he was cleared of financial misconduct following claims he had been involved in selling royal gifts and pocketing some of the proceeds.

An inquiry into the claims was headed by Charles’s then private secretary Sir Michael Peat, who said that Mr Fawcett did “infringe internal rules relating to gifts from suppliers” but the rules were not enforced and he made no secret of the gifts.

Mr Fawcett resigned following the report’s publication, but kept the prince’s patronage as a freelance fixer and party planner.

He was appointed chief executive of the Prince’s Foundation in 2018.