A mammoth hearing involving City firm Dechert, Kazakh mining giant Eurasian Natural Resources Corporation (ENRC) and the Serious Fraud Office will begin in the commercial court on Monday.

The claim is brought by ENRC and relates to its retainer of Dechert and former Dechert partner Neil Gerrard between 2011 and 2013. ENRC claims Gerrard was originally retained to conduct an internal investigation into allegations of wrongdoing concerning a subsidiary.

According to ENRC’s particulars of claim, however, Gerrard went on to deliberately leak of privileged and confidential documents to the press; to make damaging disclosures to the SFO; and to ‘balloon’ the investigation in order grossly to inflate the bills which Dechert charged to ENRC.

The respondents deny all wrong doing, saying they did not act negligently or recklessly, and were not in breach of confidence, of contract or of fiduciary duty towards ENRC. 

‘Rather, ENRC’s real complaint is that the defendants were too successful uncovering wrongdoing by certain of ENRC’s senior officers and executives, and those of its subsidiaries, including corrupt payments to senior government officials,’ Dechert and Gerrard said in their defence statement.

The hearing, which is due to be heard remotely, will start on Monday 24 May and run throughout the summer. Oral closing submissions are expected at the end of September.

A spokesperson for Dechert said: 'We have vigorously denied the allegations made against us since they surfaced. We stand by the work we did and reject any suggestion that there was any unauthorised disclosure of information to the SFO.'

The case is the latest twist in the SFOs sprawling probe into ENRC. No criminal charges have been laid.