ObjectivesTo ascertain clinicians' knowledge of their patients when requesting radiological investigations, as required legally by UK government legislation ‘Ionising Radiation (Medical Exposure) Regulations 2000’ (IRMER 2000), following the implementation of European Working Time Directive.DesignCross sectional survey.ParticipantsAll doctors requesting radiological requests every Monday, following the weekend on-call, over an 8-week period. There were no exclusion criteria.Main outcome measuresBaseline data analysis, including grade and specialty of requesting doctor, types of modality requested, knowledge of their patient, addressograph signature confirming identity and appropriateness of investigation.Results164 requests were received, the majority (61%) were made by Foundation Programme 1 (FP1) doctors and general medical specialties accounted for the highest proportion of requests (45%). Ultrasound scanning was the most frequently requested investigation (47%), closely followed by computed tomography (CT) scans (42%). Almost a third (30%) of requests were made by doctors who had not seen the patient to be investigated, predominantly by FP1 doctors (p=0.003) and more frequently by general medical specialties (p=0.001). Signatures were absent on 20% of the addressographs and overall, 10% of requests were deemed inappropriate.ConclusionsIn almost a third of radiological requests, doctors have not seen patients to be investigated, most likely as a result of shift working patterns. This does not fulfil the IRMER 2000 criteria and potentially exposes patients to unnecessary and inappropriate radiation.