Polypectomy has proven to reduce occurrence of colorectal cancer and likelihood of dying from it. Colonoscopy can be challenging due to technical or patient factors. In a small proportion of patients a complete colonoscopy is unsuccessful. Such patients either get referred to a tertiary centre with extensive experience in difficult colonoscopy or have an alternative test such as CT scan. The investigators unit has accumulated significant experience related to previously failed colonoscopy and anecdotally appears to have a high success rate in completing the procedure.