Campaigners have demanded full-disclosure from Prince Charles over a report in the Sunday Times that he accepted €3m in cash from a Qatari politician.

Campaign group Republic will be writing to Prince Charles, the government, MPs and the Charity Commission, calling on all relevant authorities to investigate and disclose the nature of Charles's financial dealings with Sheikh Hammad.

Speaking for Republic today, Graham Smith said:

"This story is shocking. Prince Charles met Sheikh Hamad in private, with no officials present and with no disclosure of the meeting in the court circular."

"The Sheikh then made three payments directly and personally to Prince Charles, totalling €3m, which Charles gave to a charity he set up to pursue his pet projects and help run one of his estates"

"Sheikh Hamad faces serious accusations over human rights and has significant financial and other interests here in the UK."

"Given that Prince Charles has direct access to the British prime minister and all government ministers, as well as all cabinet papers, this raises serious ethical questions about what the sheikh expected in return"

"Was he able to use Charles as a channel for influencing the UK government or to gain inside knowledge of government business?

"This also adds to the serious questions about Prince Charles's judgement, following from other accusations of cash-for-access and cash-for-honours."

"The Prince of Wales’s Charitable Fund also needs to answer questions about its accepting of this money and its independence from Charles."