The MERCURY Study demonstrated the accuracy, feasibility and reproducibility of Magnetic Resonance Imaging (MRI) to stage rectal cancer in a prospective, multidisciplinary, multi-centre study. However, there were differences in patient outcome, dependent upon the position of the tumour in the rectum and its height above the anal verge. Whilst the outcome was excellent for patients who underwent an anterior resection, the outcome, based upon margin involvement and quality of the specimen, was poor for patients who underwent an abdomino-perineal excision for low rectal cancer.