Evidence for the prosecution given by a participant in or accomplice to the crime being tried.
 what happens if they turn Queen's evidence?
 Example sentencesExamples
-  The 33-year-old was facing a much stiffer sentence but it was reduced after he turned supergrass and gave Queen's Evidence against a corrupt police officer.
 -  Initially he was a defendant but he turned Queen's evidence and helped secure the conviction of a gang involved in the importation of up to 40 kilos of heroin.
 -  Offenders will be guaranteed in writing that if they plead guilty and turn Queen's evidence, the sentencing judge will be told of their cooperation and they can expect a lower sentence.
 -  However, the use of Queen's evidence is always fraught with controversy as witnesses have a clear personal incentive to give the testimony.
 -  I'm glad she gave Queen's evidence but am under no illusions as to her motivations.