Since the announcement, shares in Glencore Plc have fallen 10% on the London Stock Exchange - they were at 313.75p as of 09:04 London time.

In a statement released on Tuesday July 3, Switzerland-based Glencore said the subpoena was dated July 2, 2018 and that the requested documents relate to the Glencore Group's business in Nigeria, the Democratic Republic of Congo (DRC) and Venezuela from 2007 to the present.

“Glencore is reviewing the subpoena and will provide further information in due course as appropriate,” it said.