Introduction Colonoscopic perforation remains one of the most serious adverse events associated with colonoscopy. Colonoscopies in the English NHSBCSP are performed at 61 Screening Centres. There is a robust system for capturing the details of adverse events; patients are contacted at 24 h and 30 days post procedure, Centres complete an adverse event form, reviewed by regional Quality Assurance leads, and event details are entered onto a national web based database, the Bowel Cancer Screening System (BCSS). We have previously reported an NHSBCSP perforation rate of 0.06%, and risk factors for perforation. 1 This study aimed to (1) describe perforation presentation, management and outcomes, and (2) determine perforation morbidity and mortality rates. Method We identified all reported colonoscopic perforations from the start of the NHSBCSP in 2006 up to 13/03/2014. The NHSBCSP defines perforation as: air, luminal contents or instrumentation outside the gastrointestinal tract. BCSS was interrogated to identify patient and procedure details. Centres completed a detailed online questionnaire on presentation, management and outcome. Results Of 147 perforations identified, complete data on 117 was recieved. 58.1% were male, mean age was 65.5. 69.2% were therapeutic perforations. The endoscopist visualised the perforation in 12.8% of cases (median perforation size 5 mm) applying endoclips in 80% of these. 54.5% of diagnostic perforations were in the sigmoid colon. Of 115 patients admitted to hospital, 31.3% were admitted immediately following colonoscopy, 67% represented with abdominal pain having been discharged, 1.7% were recalled following radiological investigation. 54.8% had surgery including 86.4% of diagnostic and 45.7% of therapeutic perforations. 26.1% (47.6% of those who had surgery) were left with a stoma. Post Perforation Morbidity defined as an in-patient complication or new diagnosis was 19.7%. Median hospital stay was 9.5 days (range 0–51 days). 25.2% were admitted to the Intensive Care Unit. The mortality rate was 0.87%. Conclusion This is the largest case series reporting outcomes after colonoscopic perforation in the UK. The colonoscopist recognised the perforation during colonoscopy in only 12.8% of cases, the majority representing with abdominal pain after a mean of 2 days. 44.3% of perforations admitted were successfully managed conseravtively including 13.6% of diagnostic and 53.1% of therapeutic perforations. Over a quarter of perforations admitted are likely to leave hospital with a stoma. A post perforation morbidity rate of 19.7% and mortality rate of 0.87% compares favourably with other series. Disclosure of interest None Declared. Reference Rutter MD, et al . Endoscopy 2014:90–97