A charity founded by Prince Charles may face a Charity Commission investigation after a complaint was lodged about its independence.

Republic, an anti-monarchy campaign, has written to the Charity Commission, complaining that the Prince’s Foundation for Integrated Health (FIH) has compromised its independence by pursuing a personal vendetta of Prince Charles, who is honorary president of the charity.

As evidence, Republic cites a complaint made five years ago by former chair of FIH Sir Michael Peat.

At the time, Sir Michael complained to the University of Exeter about remarks its professor of complementary medicine, Edzard Ernst, had made about the Smallwood report, which advocates complementary medicine.

Republic argues that the complaint from Sir Michael, who was – and still is – private secretary to Prince Charles was made at the behest of the monarch:

“Since the report was published Professor Ernst has claimed that the complaint was, in fact, printed on Clarence House letterhead,” says the letter.

“This suggests that the complaint came from Prince Charles, rather than the FIH. Further investigation reveals that the Smallwood report was commissioned by Prince Charles not by the FIH.”

A spokesman and FIH have denied that Prince Charles has used the charity to promote his own views.

The Charity Commission is assessing the complaint to decide whether a formal investigation is necessary.