Evidence for the prosecution given by a participant in or accomplice to the crime being tried.
〔英格兰律〕（刑事被告向法院提供的）对同案犯不利的证据
what happens if they turn Queen's evidence?
如果他们供出对同犯不利的证据，会怎么样？
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.