The term ‘fundamental dishonesty’ is referred to in both Civil Procedure Rules (CPR) 44.16(1) and Criminal Justice and Courts Act (CJCA) 2015, Section 57. CJCA 2015, Section 57 allows for an entire personal injury claim to be dismissed, including any genuine elements, on the basis that the claimant has been fundamentally dishonest in relation to the primary claim or a related claim.
https://www.hja.net/fundamental-dishonesty-and-fraud-in-a-personal-injury-cases/