Clifford Chance (CC) is facing a professional negligence claim from litigation funders over its work on the high-profile Excalibur Ventures dispute.

Excalibur hired CC to act for it on a high-profile $1.6bn claim against Texas Keystone and Gulf Keystone over petroleum interests in Iraqi Kurdistan. The claim was dismissed last autumn, with Lord Justice Christopher Clarke awarding the defendants costs on an indemnity basis in October, making four groups of third-party funders collectively liable for over £23m.