Rio Tinto director John Varley has stepped down from the mining giant's board after being charged in a high-profile UK corruption investigation.
Mr Varley, a former chief executive of Barclays, is among the four of the bank's former senior executives charged by the UK's Serious Fraud Office with conspiracy to commit fraud by false representation and unlawful financial assistance.
The charges follow an investigation into undisclosed payments to Qatari investors during an emergency fund raising by Barclays in 2008, when Mr Varley headed the bank.
Rio said in a statement on Wednesday that Mr Varley had resigned with immediate effect, but did not mention the charges.
"The board holds him in the highest regard and will miss his valuable insight," chairman Jan du Plessis said.
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"Personally, I am not only losing a senior independent director, but a close colleague, whose wisdom and support I am going to miss tremendously."
Mr Varley joined Rio's board as an independent director in September 2011, and was the chair of the board's remuneration committee.
He was also tasked with leading the process to select a new chairman for Rio Tinto after Mr du Plessis announced in May he will retire before the 2018 annual general meeting, and take up a role as chairman of UK telco giant BT Group.
Rio said an announcement about the appointment of a new independent director and chair of the board's remuneration committee will be made in due course.
Rio shares were down $1.49, or 2.5 per cent, at $58.23 at 1205 AEST, in a significantly weaker market.
