The number of people claiming for personal injury after being involved in a road traffic accident (RTA) in the UK continues to soar. In April 2015, the UK Government intervened to implement measures aimed at reducing the prevalence of fraud within such personal injury claims. However, these reforms did not include claims for mental disorder that arise because of a RTA despite being responsible for substantially larger payouts in comparison with claims for whiplash. The present study examines the assessment practice for detecting fraudulent claims of this nature using a mixed methods survey analysing UK medico-legal professionals’ assessment methodologies (N = 37). The findings suggest comprehensively that assessment practices in this field are idiosyncratic. The findings evidence limitations in all aspects of the assessment process from medico-legal assessors being asked to undertake examinations without the presence of medical records to 44% of examiners being unaware of the three types of malingering. The article concludes with recommendations for improving both assessments and the assessment process for assessing RTA claimants in the UK.