There is a large evidence base around prostate cancer. Most of this concentrates on which stages of the disease to treat with which modality. The purpose of this study is to try and determine from the literature an evidence based radiotherapy treatment technique. The evidence is examined on prostate and patient motion, the effect of bladder and rectum filling, patient positioning and error detection with portal imaging. The technique derived is patient supine or prone with empty bladder and bowel. A simple leg immobilisation device is recommended, with set-up to couch height. The required margins are 13.2 mm laterally, 18 mm anterior-posteriorly and 21.3 mm cranio-caudally using a three-dimensional margin recipe. It is shown that an intensive portal imaging routine is required to demonstrate that systematic set-up errors are below 5 mm.