From the MHRA perspective there is a legal requirement for the sponsor to ensure GCP compliance throughout the course of the trial. While a sponsor may review the CROs SOPs prior to contracting activities, these can change during the trial period. Therefore, in order for the sponsor to maintain GCP oversight they should have access to the CROs SOPs when required to undertake their oversight obligations. This could be via a number of methods depending on how and when the oversight is undertaken for example, continuous access or notification of when SOPs have changed or during subsequent audits (although this method would be retrospective) to ensure these are still acceptable.