Arag Plc v Jones & Anor  EWHC (Comm) (18 December 2020).
Where there were two Claimants but the ATE police only covered one Claimant, the non-covered party would be jointly and severally liable for the Defendant's costs. The ATE insurer was therefore only liable for 50% of the agreed Defendant's costs.
The lesson here is to ensure that any policy covers all relevant parties and if it does not that you ensure you advise of the potential implications.
As an interesting side note, the Defendant was not responsible for the Costs Lawyers fees as that instruction was not given jointly.