Dechert has been dealt a blow in its long-running fee dispute with a former client, with a High Court judge in the U.K. ruling Friday that the company can proceed in its attempt to recover millions of dollars from the firm.

Eurasian Natural Resources Corporation accused Dechert of “systematic and gross overcharging” after the firm billed the London-based mining company $20.3 million for 23 months of work relating to a criminal investigation by the U.K.’s Serious Fraud Office.