Deals cut by Eurasian Natural Resources Corp, the embattled FTSE 100 miner, have been lambasted for “opaque concession trading” costing the Democratic Republic of Congo $725m, in a hard-hitting report today by Kofi Annan’s Africa Progress Panel.

The report calculates the Congo incurred losses of $1.36bn between 2010 and 2012 as a result of the alleged undervaluation of state assets in five mining deals, three of which involve ENRC. In a further development, it emerged that the UK’s Serious Fraud Office is preparing to send investigators to the Congo as part of its criminal probe into ENRC.

ENRC acquired concessions in Congo via offshore vehicles controlled by Dan Gertler, an Israeli businessman close to President Joseph Kabila who has been central to a string of secretive deals in the mineral rich country in the past decade.