Part I: Recognition and usage 18 Bringing medical evidence of torture to international tribunals By Renate Winter President of the Special Court for Sierra Leone International law imposes the responsibility to take effective and appropriate measures to prevent and punish acts of torture and to proceed to a prompt and impartial investigation when confronting allegations of torture. The Istanbul Protocol, compiled by leading medical and other professionals, provides extensive guidelines for the effective investigation and documentation of torture. As stated in the Istanbul Protocol, the purpose of investigation and documentation is, in part, the facilitation of prosecutions or, as appropriate, disciplinary sanctions for those indicated by the investigation as being responsible. Medical experts can play a crucial role in generating evidence. They can support the work of the prosecution and the court by examining alleged victims of torture, compiling medico-legal reports and presenting their findings as expert witnesses during the legal proceedings. In cases before the international criminal tribunals, evidence must meet basic requirements before it can be admitted and considered by the judge. The assessment is generally flexible and the touchstone for admissibility is the relevance and probative value of the evidence. Evidence may be excluded if its probative value is considered to be substantially outweighed by the need to ensure a fair trial. It may also be excluded if it was obtained in a way which raises substantial doubt about its reliability or if its admission would damage the integrity of the proceedings. As a matter of law, corroboration is not required generally nor in particular in relation to testimony of victims of sexual violence, which is significant to cases alleging acts of sexual violence that amount to torture. Use of expert medical evidence Additional rules apply to the admissibility of expert evidence at the international criminal tribunals. An expert is a person who by virtue of some specialised knowledge, skills or training