11 August Case Updates Various Claimants v Mercedes-Benz Group and Others [2026] EWHC 1753 (KB) 06. Rules and Regulations, 11. Report Writing, 14. Changing your opinion, 08. Working with Instructing Parties, 15. Giving Oral Evidence, Prohibited Defeat Devices, Pan NOx The trial dealt with liability issues relating to the alleged use of prohibited defeat devices. That is, devices which reduce the effectiveness of a vehicle’s emission control system for which there is no excuse or applicable exception. The judge criticised three of the expert witnesses for not complying with their duties under Part 35, and praised others.