Confidentiality The Caldicott Principles for use of identifiable data will be used. In accordance with University and NHS policy, to ensure satisfactory integrity both of research data and confidential patient information, the procedural data will be stored in anonymised form on a fully archived hard disk drive, with additional backup on long term optical storage media, while patient identifiable data will be stored on computers located within the NHS facility. Linkage between them will be in the form of paper records, which will be retained within the NHS premises. If confidentiality needs to be broken we will seek advice from the local ethics committee.