Abstract Aims Complicated diverticular disease is associated with colonic neoplasia rates of 7.8% to 10.9%. ACPGBI guidelines recommend optical or virtual colonoscopy six weeks following an attack of acute complicated diverticulitis unless performed within the preceding two years. It has been posited that flexible sigmoidoscopy may be sufficient to rule out malignancy given that diverticulitis predominantly affects the sigmoid colon. Five years of practice at a 600-bed hospital was audited to the ACPGBI standard and malignancy rates and locations investigated. Methods All emergency admissions coded for acute complicated diverticulitis from January 2017 to December 2022 were included. Patient electronic records were reviewed retrospectively for demographic data, operation notes, as well as radiology, endoscopy and histology reports. Results A total of 197 patients were included in the study period. 97 cases underwent emergency or semi-elective resection within one year. 8 patients had colonic visualisation in the two years prior to their attack, leaving 92 cases in whom colonic visualisation was indicated. 44 patients had colonoscopy, 22 had flexible sigmoidoscopy, 2 had CT colonography and 24 had no further imaging. 7 malignancies were identified, 5 from resection specimens and 2 from endoscopy. All tumours were in sigmoid colon. Conclusions The ACPGBI standard was met in 50% (46/92) of cases. If flexible sigmoidoscopy were deemed acceptable this would increase to 74% (68/92). Malignancy was identified in 4% (7/197) of cases. All malignancies were in the range of flexible sigmoidoscopy, suggesting full colonoscopy may be superfluous. Less extensive endoscopy may reduce procedure duration, bowel preparation and patient discomfort.